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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738201 (2009) https://doi.org/10.1117/12.846779
This PDF file contains the front matter associated with SPIE
Proceedings Volume 7382, including the Title Page, Copyright
information, Table of Contents, the Conference Committee listing and the Introduction.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738202 (2009) https://doi.org/10.1117/12.836020
This paper will give an overview on some recent laser radar work at the Swedish Defence Research Agency (FOI). The
activities include range gated imaging, scanning and 3 D ladars and flash imaging 3 D ladars. Example of data from
different campaigns will be presented together with examples of modelling efforts. Example of potential applications
will be discussed.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738203 (2009) https://doi.org/10.1117/12.835136
Practically no applications exist for which automatic processing of 2D intensity imagery can equal human visual
perception. This is not the case for range imagery. The paper gives examples of 3D laser radar applications, for which
automatic data processing can exceed human visual cognition capabilities and describes basic processing techniques for
attaining these results. The examples are drawn from the fields of helicopter obstacle avoidance, object detection in
surveillance applications, object recognition at high range, multi-object-tracking, and object re-identification in range
image sequences. Processing times and recognition performances are summarized. The techniques used exploit the
bijective continuity of the imaging process as well as its independence of object reflectivity, emissivity and illumination.
This allows precise formulations of the probability distributions involved in figure-ground segmentation, feature-based
object classification and model based object recognition. The probabilistic approach guarantees optimal solutions for
single images and enables Bayesian learning in range image sequences. Finally, due to recent results in 3D-surface
completion, no prior model libraries are required for recognizing and re-identifying objects of quite general object
categories, opening the way to unsupervised learning and fully autonomous cognitive systems.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738204 (2009) https://doi.org/10.1117/12.835943
We will overview organized airflows, turbulent and laminar structures in the atmospheric boundary layer and the free
atmosphere newly detected by a 3D-scanning coherent Doppler lidar system (3D-CDL).
Study of clouds becomes important especially in recent years, since they play an essential role in global climate systems
and the earth environment. The aerosol-cloud interaction is not enough to evaluate aerosol indirect effect. Air-motion is
the key factor that connects aerosols and clouds especially in the atmospheric boundary layer. Using the 3D-CDL, we
detected such various kinds of atmospheric phenomena as plume, streaks, invisible dust-devils, fog, fire-work, local
front, downburst, wake of buildings, gravity waves, Kelvin-Helmholtz instability waves, sea-breeze fronts, fine-weather
cumulus, low-level stratus, mid-level clouds, mammatus clouds and cirrus clouds etc. Some of these phenomena are
firstly observed by the 3D-CDL. We simulated some phenomena by using a Large Eddy Simulation (LES) model and
compared the simulated structures with those observed by the 3D-CDL.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738205 (2009) https://doi.org/10.1117/12.836606
Accidents to airliners caused by air turbulence have been increasing in recent years. At present there is no sure way of
avoiding encounters with clear air turbulence (CAT) because conventional airborne weather radars cannot detect
turbulence in clear conditions. The Japan Aerospace Exploration Agency (JAXA) is therefore developing a Doppler
LIDAR (Light Detection and Ranging) which can measure wind speeds ahead of an aircraft even in clear air. Turbulence
prediction in flight has already been demonstrated using experimental Doppler LIDARs, and the latest prototype aims at
turbulence detection up to 5 nautical miles (9 km) ahead at jet airliner cruising altitudes. Wind velocity measurement by
LIDAR is difficult at high altitude because of low aerosol particle density. Regular atmospheric observation flights are
therefore being made to establish the basic specifications of a practical device. Furthermore, since air turbulence
information should be displayed on the flight deck, a graphical turbulence display is also being studied. This paper
describes the development of the airborne wind measurement system and presents examples of flight experiment results.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738206 (2009) https://doi.org/10.1117/12.838432
Laser diode pumped single frequency, narrow-linewidth solid state lasers have important applications in coherent
detection systems. This paper reports two kinds of diode pumped single frequency solid state lasers with wavelengths of
1319nm and 2μm, respectively. The LD pumped monolithic non-planar ring resonators (NPRO) are designed to
generate the single frequency operation. High efficiency single frequency lasers were obtained in the 1319nm NPRO
Nd:YAG laser and the 2μm NPRO Tm:YAG laser.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738207 (2009) https://doi.org/10.1117/12.836813
Semiconductor Lasers (also known as Laser Diodes, LDs), have many
unique properties and advantages and found wide applications in variouse fields. The
super high conversion efficiency of high power single emitter semiconductor lasers
and their arrays, commonly achievable values of them being in the range of 50%-80%,
makes them particularly suitable for applications as the ideal pumping source for solid
state lasers and also as widely used in material processing and medicine. Yet
semiconductor lasers also have shortcomings, the poor beam quality of multi-mode
semiconductor lasers and laser arrays usually severely restricted their applications.
The present paper mainly addresses the semiconductor laser arrays design and
fabrication technologies, with particular emphasis placed on the beam shaping
principles and methods. The high power semiconductor lasers in the wavelength range
between 800nm and 1100nm have been reviewed and analyzed. The topic of the
electrical-to-optical conversion efficiency enhancement has been addressed in some
detail. The high power single emitter lasers and LD bars have been fabricated and
their performance characterized. The beam divergences of LDs in the vertical and
parallel directions have been addressed and analyzed. The beam collimation has been
analyzed and experimentally performed for the single emitter and LD bars. Beam
combining methods and fiber coupling have been summarized and experimentally verified, with specific efficiency data for beam combining and fiber coupling being
presented and analyzed.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738208 (2009) https://doi.org/10.1117/12.839584
Laser pulses with different pulse durations between 50 fs and 12 ps are used to ablate different types of solid targets.
With the help of time-resolved shadowgraphy, the ultrafast dynamics associated with femtosecond laser ablation of solid
materials is experimentally investigated based on the commonly used pump-probe technique. It is revealed that both
photothermal and photomechanical mechanisms exist in the ablation processes for laser fluence far above the target
ablation threshold. From the recorded shadowgraphs, it is revealed that the material ejection due to femtosecond laser
ablation of solid materials has a typical velocity of 105 - 104 m/s. Such high jet velocities can lead to specific impulse of
104 - 103 s, which is much higher than the upper limit of the specific impulse of chemical propulsion (500 s). The
so-called ablative laser propulsion with high specific impulse can be thus realized. Momentum coupling coefficient is
determined through using a homemade torsion pendulum with a minimum measurable momentum of ~2x10-9 N·s. The
dependence of the ultrashort laser ablation generated momentum is investigated on laser energy fluence and pulse width.
The main findings include: 1) As the pulse width increases, the laser generated momentum first increases rapidly and
then remains almost constant; 2) For 50 fs pulses, optimal laser fluence exists that leads to the maximum momentum for
aluminum and copper targets. At the optimal laser fluence, it is mostly the photomechanical mechanism that is
responsible for material removal, and in this case the ablated material also has relatively lower jet velocity.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738209 (2009) https://doi.org/10.1117/12.836888
This paper introduces the recent development of 3D imaging LADAR (LAser Detection And Ranging) in
Mitsubishi Electric Corporation. The system consists of in-house-made key devices which are linear array: the laser,
the detector and the ROIC (Read-Out Integrated Circuit). The laser transmitter is the high power and compact planar
waveguide array laser at the wavelength of 1.5 micron. The detector array consists of the low excess noise Avalanche
Photo Diode (APD) using the InAlAs multiplication layer. The analog ROIC array, which is fabricated in the SiGe-
BiCMOS process, includes the Trans-Impedance Amplifiers (TIA), the peak intensity detectors, the Time-Of-Flight
(TOF) detectors, and the multiplexers for read-out. This device has the feature in its detection ability for the small
signal by optimizing the peak intensity detection circuit. By combining these devices with the one dimensional fast
scanner, the real-time 3D range image can be obtained. After the explanations about the key devices, some 3D imaging
results are demonstrated using the single element key devices. The imaging using the developed array devices is
planned in the near future.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820A (2009) https://doi.org/10.1117/12.836267
Airborne and spaceborne Laser sounding technology has been greatly improved, and they play important role in both
science and economy. Basing on our study, airborne laser 3D imaging technology for earth observation, the data
processing technology for laser sounding target, and laser altimeter for lunar sounding of China are discussed. Finally,
the future development about space laser sounding is discussed.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820B (2009) https://doi.org/10.1117/12.835363
We demonstrate a catheter-based complex swept-source optical coherence tomography (SS-OCT) system using a 3x3
Mach-Zehnder quadrature interferometer and an ultra-small optic probe. Design and fabrication of fiber lens for ultrasmall
optic probes are presented first. We compare in detail measured performance with expected theoretical
performance. Then, we present a 3x3 Mach-Zehnder quadrature interferometer to acquire a complex interferometric
signal for SS-OCT. We introduce an unbalanced differential detection method to improve the overall utilization of
optical power and provide simultaneous access to the complementary phase components of the complex interferometric
signal. No calculations by trigonometric relationships are needed. We compare the performance for our setup to that of a
similar interferometer with a commonly used balanced detection technique. We demonstrate complex conjugate artifact
suppression of 27 dB obtained in our swept-source optical coherence tomography using our unbalanced differential
detection. OCT in vivo and ex vivo images shown in this presentation indicate that our catheter-based complex SS-OCT
system is capable for imaging of biomedical tissues and inside organs for human and animals.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820E (2009) https://doi.org/10.1117/12.837138
The large band-with of super continuum Laser permits long path examination of large continual
spectral regions to measure multi-species present simultaneously along the path. Herein statistical
calculation and inversion with MLE on base of multivariate normal distribution model given focus on
testing engineering capability of simultaneous multi-species detection with MODTRAN4 return under
different cases of widely varied noise and atmospheric aerosol extinction. Simulation on available
waveband of commercial super continuum Laser produce perfect results that agree with true
concentration of multi-species and show complete approach advantages of abundant wavelength lines
selected with a super continuum LIDAR: high accuracy, low FAR and robust result.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820F (2009) https://doi.org/10.1117/12.835226
Recently, continue-wave blue laser generated by frequency doubling of the diode-end pumped neodymium doped
lasers operating at the 4F3/2→4I9/2 transition have been extensively explored. But this way is limited by the
considerable re-absorption loss caused by thermal population of the lower laser level for the oscillation of
quasi-three-level laser. Another efficient way to obtain blue laser is based on summing frequency of the neodymium
doped laser operating at the 4F3/2→4I13/2 transition. Unlike the three-level system of the 4F3/2→4I9/2 transition,
stimulated emission at the 4F3/2→4I13/2 transition is a four-level system that can provide a low-threshold and stable
laser output due to the lack of sensitive temperature dependence of the transition rate. High power blue laser has
been achieved in this way. In this paper, we report a high power blue laser output is obtained by intracavity
sum-frequency-mixing of a diode-side-pumped Q-switched Nd:YAP laser operating at 1.3μm with two LBO crystals.
An LBO crystal with type-I critical phase matching and the other crystal with type-II critical phase matching were
used for the second harmonic generation and the third harmonic generation, respectively. In view of the analysis of
the cavity stability, a four-mirror folded cavity was designed and the output characteristics were theoretically
analyzed. Experimental characteristics obtained were shown to be in agreement with the theoretical analysis. 3.2W
average power at 447nm and 1.3W average power at 446nm blue laser outputs were achieved at 1kHz with pulse
width of 10ns from the 1341.4nm laser beam polarized along the c crystalline axis and the 1339.2nm laser beam
polarized along the a crystalline axis, respectively. The 447nm blue laser corresponds to a red-to-blue conversion
efficiency of 30%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820G (2009) https://doi.org/10.1117/12.835318
The laser diode side-pumped electro-optical Q-switced Nd:YAG laser of high single pulse output energy were studied.
Two alternated semicircular LDA module was used to directly side pump the Nd:YAG crystal of a series of two-rod.
Each module consists of 30 laser diode which peak power is 100W. KD*P crystals is used as the electro-optic Q switch.
And the ABCD law of the Gaussian beam propagation is applied to calculate the area of the stability of the resonator
cavity, and a more reasonable parameters of the resonant cavity is given. A 1064nm dynamics laser that maximum output
energy of 140mJ and pulse width of 10ns is obtained at a repetition rate of 20Hz when the pump energy is 1200mJ.The
optical-optical conversion efficiency is 11.7%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820H (2009) https://doi.org/10.1117/12.831355
Superresolution is very important in imaging and optical storage systems, and has attracted much attention. In this
article, concentric three-zone phase plate with 0, pi, 0 phase variation has been investigated numerically to show that this
kind of phase plate can be used to obtain three dimensional superresolution. Focal depth, focal shift, full width half
maximum, superresolution effect are listed for different radii of the phase zones, which paves the way for design of the
phase plate, such as for purpose of radial superresolution with high focal depth in optical storage.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820I (2009) https://doi.org/10.1117/12.829459
Signal detection plays a very important part in information times, which includes optical signal detection and
electronic signal detection. Without question, 21 century is an optical times, so the importance of the optical signal
detection becomes obvious. Optical detection includes direct detection and indirect detection (coherent detection).
Direct detection is a method which only measures the amplitude of the signal and also be used in the measurement for
strong signal. In contrast in indirect detection other parameters of the received electrical field can be modulated, such as
its amplitude, frequency or phase. Coherent detection can be performed using two different techniques: heterodyne
detection and homodyne detection. The coherent detection has much more sensitivity improvement over direct
detection. However, some errors arise because of the two unstable signals, i.e., local beam and signal beam. Therefore,
balanced detection technique can solve the question.
In this paper, balanced detection technique was analyzed, which also was applied in signal measurement for lidar.
Firstly, Mathematical modeling of the balanced detection process is deduced. Secondly, a numerical simulated system is
established with software LABVIEW. Signal-to-noise ratio of the balanced detection is much two times than that of
normal coherent detection technique. Furthermore, this balanced detection technique, which also be used in
measurement for wind, not only Doppler shift can be obtained, but whether the Doppler shift is positive or negative can
be distinguished, in other words, can know the direction of wind. Last but not least, the experiment results is well
consisted with the simulated results, which shows that signal-to-noise ratio has been improved obviously.
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Qiu-hua Wan, Yong Jiang, Shao-chang Su, Ying Sun, Yong-zhi Wu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820J (2009) https://doi.org/10.1117/12.836053
In order to achieve the dynamical detection and real-time analysis of the movement status of the magnetic fluid,
according to the difficulties of the detection of the magnetic fluid, established a high-speed acquisition and processing
system of laser speckle signal on the magnetic fluid. First of all, the FPGA (EP2C8T144C8N) drived the linear array
CCD(TCD1501D) to scan in the corresponding time sequence given by the computer, collected the laser speckle
interferometric image in rapid change on the surface of the magnetic fluid, which followed the movement of the magnetic
fluid, and the signal collected by CCD was converted into the digital data through the high-speed A/D convertor and
stored into the internal buffer FIFO of the FPGA, whose width and depth were designed by the user as required. Then,
the FPGA sent the digital signal of the laser speckle interferometric images into the computer through the USB2.0 highspeed
differential bus, whose transmission rate can reach 480Mb/s in theory. Finally, the distribution of the laser speckle
on the magnetic fluid was messy and random, which carried certain information about the surface of the magnetic fluid, based on the theories of the statistic correlation and the subdivision of images, analysing and processing the laser
speckle interferometric images, indirectly got the movement status of the magnetic fluid under the electromagnetic field.
The experimental results show that: the High Speed Acquisition and Processing System has the advantage of full-court,
non-contact, non-invasive, high-precision and high reliability and so on. The detection resolution of high speed
acquisition and processing system is superior to 1m and the sample rate is 3Msps, which basically meets the
requirements of the magnetic fluid movement state detection.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820K (2009) https://doi.org/10.1117/12.836395
With the development of laser technology, Three-Dimensional (3D) imaging sensors based on Laser Radar (LADAR)
gradually possess vast application in complicated battlefield of modern warfare. LADAR can detect much more targets
than other sensors, such as infrared imaging and radar imaging. Range image and intensity image can be obtained
through using LADAR, and they are suitable for automatic target recognition. At present the research of automatic target
recognition technology for LADAR is a hot problem. Main work of this paper is composed of three parts: Firstly, current
research and application of automatic target recognition technology for LADAR are demonstrated; Secondly, main
problems in automatic target recognition for LADAR are thoroughly analyzed, including problems in five stages: preprocessing,
target detection, feature extraction, founding pattern database and performance evaluation; Finally, a detailed
survey is set forth about technical approach of automatic target recognition for LADAR, including six components: preprocessing,
target detection, feature extraction, recognition, modeling and simulation, performance evaluation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820L (2009) https://doi.org/10.1117/12.835403
At present, bidirectional transmission over a signal fiber is applied in many fields, such as WDM. Bidirectional
transmission over a signal fiber can reduce the required number of fibers and uses one optical source, so it is lower cost
than unidirectional transmission counterparts. In this paper, the phase-noise counteracting characteristic in the
bidirectional transmission over a polarization maintaining fiber (PMF) due to different polarization rotating angle of
counter-propagation light is analyzed. The analyzing results indicate that the bidirectional system with a special
polarization rotating angle of counter- propagation light has a good property that can counteract phase noises coming
from external factors such as temperature etc. reciprocal factors. Thus, phases' fluctuation can be reduced and it has the
advantages of measuring phase change and achieving phase calibration. Based on the result, using Jones matrix, the
established system is discussed and the phase difference owing to nonreciprocal parameters such as Faraday
electromagnetic induction is obtained. So the calibration of phase is achieved according to the measured results.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820M (2009) https://doi.org/10.1117/12.834901
In order to reach a green Olympics in 2008, an unprecedented environmental experiment jointly
launched by the Beijing municipal government and the Chinese Academy of Sciences (CAS) was
carried out. AIOFM (Anhui Institute of Optics and Fine Mechanics Experiment) took part in the
campaign with an elastic/non-elastic lidar to measure the aerosol distribution and the boundary layer in
summer in Beijing. With the combining solution of the Raman lidar and the elastic lidar equation, the
important optical parameters of the aerosols (extinction coefficient, backscatter coefficients thus the
lidar ratio) were attained. The lidar ratio on July 22 varied from 10sr to 30sr. Since the vertical
distribution of the lidar ratio demonstrate different microphysical characteristics in the lower and upper
parts of the cloud, so probably the cirrus with the mean lidar ratio of 25sr at the height of 6km can be
assumed. On the other hand, a well-mixed boundary layer was observed. Taking into account the
effects of the multiple scattering (5%-10%),we obtain a single-scattering optical depth of 0.15.The
boundary layer also offered the explanation of the steady ozone concentration measured by the DOAS
system at the same position of the observing site.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820N (2009) https://doi.org/10.1117/12.836600
After the nonlinear optical phenomena were discovered, people began to research the techniques
to detect the optical nonlinearities of materials. In this paper, a new optical nonlinear measurement
technique-4f coherent imaging system is recommended. The system has many advantages: single shot
real-time measurement, simple experimental apparatus, high sensitivity, being able to detect the magnitude
and sign of both nonlinear absorption and refraction at the same time, low requirement of beam spatial
distribution, and so on. This paper introduces the theory of the 4f system and makes a detailed review and expounds
development and application of the 4f coherent image system. The nerve of the experiment is improving the phase
diaphragm. The shape of the diaphragm from the double-slits to the small rectangular object, and transition
to a circular aperture, finally forming a circular phase diaphragm, which is a circular aperture in the center
add a phase object. Following these diaphragm changes, the sensitivity of the system is greatly improved.
The latest developments of the system are series-wound double 4f coherent imaging technique and the
time-resolved pump-probe system based on NIT-PO. The time-resolved pump-probe system based on NIT-PO can be
used to measure the dynamic characteristics of excited states nonlinear absorption and refraction.
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Xiaomin Jin, Sean Jobe, Simeon Trieu, Benafsh Husain, Jason Flickinger, Bei Zhang, Tao Dai, Xiang-Ning Kang, Guo-Yi Zhang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820O (2009) https://doi.org/10.1117/12.834103
In this paper, we present an analysis of gallium nitride (GaN) quantum-well (QW) laser diode (LD) by numerical
simulation. Here we discuss three aspects that are crucial to our analysis. First, the transverse mode pattern is studied,
and our current GaN diode laser structure is discussed with optical waveguide mode analysis. Then we compare the QW
design of the laser and maximize laser modal gain. Finally, we report the influence of the electron block (e-block) layer
on lasing performance of our design.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820P (2009) https://doi.org/10.1117/12.832359
A simple heterodyne interferometer associates with phase to amplitude conversion and amplitude sensitive technique is
proposed. The excess noise and the quantum noise introduced by the autocorrelations between sensing beam and local
oscillator beam are reduced at suitable phase bias. Meanwhile, the differential phase arises from target displacement is
detected by optical differential and optical additive operations. The amplitude and phase quadrature are also achieved
simultaneously in proposed interferometer.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820Q (2009) https://doi.org/10.1117/12.835041
Recently, low-level laser therapy (LLLT) has been reported to have a photobiomodulation effect on bio-tissues. Our aim
was to evaluate the effect of low level GaAlAs laser on bone regeneration around bone defect sites created surgically in
rabbit femur. Thirty rabbits were randomly divided into an experimental and a control groups. A GaAlAs semiconductor
diode laser was applied in the experimental group( λ = 808nm, P =75mW, (symbol) =0.4mm,t=5min,
ρE=28J/cm2)immediately after surgery once a day for 3 consecutive days with no irradiation in the control group.
Rabbits were sacrificed on the 7th, 14th, 21th days after surgery (DAS) and femur samples were prepared for bone
histomorphometry analysis. The results showed that the bone volume, the osteoid volume, osteoblast surface and the
mineral apposition rate in the laser group were higher statistically (P<0.05) than those indices in the control group at
different periods. These data revealed that LLLT can enhance bone regeneration. LLLT seems to have a clinical
application in promoting bone healing around implant in the future.
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Guang Shi, Yuxiao Wang, Xueru Zhang, Kun Yang, Yinglin Song
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820R (2009) https://doi.org/10.1117/12.834226
We demonstrate theoretically and numerically how to identify and separate the high-order absorptive and refractive
nonlinearities. We give, for multiphoton absorption, the formulas of the nonlinear imaginary phase shift, and thus the
normalized transmittance of open aperture Z-scan. In order to determine the two-photon and three-photon absorptions
immediately, we also give two empirical formulas with considerable accuracy, which require only the nonlinear
normalized transmittance at the focus. Moreover, we show the Gaussian decomposition method and zeroth-order Hankel
transform to obtain the complex optical field at the far-field aperture. We find that the former frequently used fails to
describe the propagation process for the large nonlinear imaginary phase shift. The influence of linear transmittance of
aperture and the multiphoton absorption on the measurement of nonlinear refractive index are also analyzed in detail. In
addition, we show the competition relationship between low-order and high-order optical nonlinearities, depending on
the intensities at different z positions.
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Wenjing Tang, Dechun Li, Shengzhi Zhao, Guiqiu Li, Kejian Yang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820S (2009) https://doi.org/10.1117/12.834451
It has been proved theoretically and experimentally that a doubly Q-switched laser with both an electro-optic (EO)
modulator and a GaAs saturable absorber can obtain more symmetric and shorter pulse with high pulse peak power,
which is more useful in some applications. Therefore it is essential to optimize this kind of doubly Q-switched lasers. In
this paper, by combining the single-photon absorption (SPA) and two-photon absorption (TPA) processes of GaAs
saturable absorber, and considering the Gaussian spatial distributions of the intracavity photon density and the initial
population-inversion density as well as the influence of the electro-optic (EO) Q-switch, we introduce some new
normalized parameters and provide the new normalized rate equations for a diode-pumped doubly Q-switched laser with
both an electro-optic (EO) modulator and a GaAs saturable absorber, which are solved numerically. The key parameters
of an optimally coupled doubly Q-switched laser are determined, and a group of general curves are generated for the first
time. These key parameters include the optimal normalized coupling parameter, the optimal normalized saturable
absorber parameters, and the normalized parameters of the electro-optic (EO) Q-switch, which can maximize the output
energy. Meanwhile, the corresponding normalized energy, the normalized peak power and the normalized pulse width
are given. The curves clearly show the dependence of the optimal key parameters on the parameters of the gain medium,
the GaAs saturable absorber, the electro-optic (EO) Q-switch, the resonator and the spatial distributions of the intracavity
photon density. These optimal results are compared with those of the optimized single Q-switched lasers. Sample
calculations for a diode-pumped Nd:YVO4 laser with both an electro-optic (EO) modulator and a GaAs saturable
absorber are presented to demonstrate the use of the curves and the relevant formulas.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820T (2009) https://doi.org/10.1117/12.834998
An Er/Yb co-doped double cladding fiber laser pumped at 980 nm was optimized. The double-cladding fiber laser with
whole fiber was obtained by end-pumping and utilizing fiber bragg grating as a resonator. The output power of laser was
analyzed along the changes of output grating reflectance (L=10m) as well as the fiber length (R2=4%). Consequently, a
fiber with 4 m Er / Yb co-doped double cladding was employed as gain medium while a fiber of which the reflectance
was approximately 15% was used as output resonator mirror. Thereafter the technical indexes of EYDF(Er / Yb Double
cladding Fiber) were measured. The absorption maximum of fiber core Er3+ was higher than 30dB/m and material gain
maximum was observed at 1535nm. Moreover, the diameters of fiber core and inner cladding of double-cladding fiber
grating were 6μm and 125μm respectively however the diameters of fiber core and inner cladding of Er/Yb co-doped
double cladding fiber were 7μm and 130μm separately.According to the experimental data, a fiber laser with 4 m Er / Yb
co-doped double cladding and launched maximum pump power of 3.4 W was set up. Proposed laser shows the
maximum output power of 1.25 W and slope efficiency of 40%.
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Yong Cheng, Chaowei Mi, Yang Liu, Xu Liu, Xue Yang, Huisheng Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820U (2009) https://doi.org/10.1117/12.835248
Phase locking and coherent beam combination of two individual double-clad fiber lasers by a novel extra-cavity mutual
injection-locking method based on a corner-cube are proposed and experimentally demonstrated. Steady interference
stripes with high contrast ratio(about 81.7%) are observed. The output power of the phase-locked array exceeded 10W
and the power combining efficiency is about 80%. No power-restriction optical components are utilized in our phaselocking
experiment and the output power can be further up-scaled.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820V (2009) https://doi.org/10.1117/12.832285
Photoacoustic tomography(PAT) is a new imaging modality of biological tissues. It merges the contrast advantage of
pure optical imaging with the resolution advantage of pure ultrasound imaging. A numerical simulation method of spatial
resolution in photoacoustic tomography was studied. The full width at half maximum (FWHM) of point spread function
(PSF) was calculated to determine the spatial resolution. The effectiveness of the simulation method was indicated by
experiment. The relationship between spatial resolution and filter's cutoff frequency and active detector aperture size
was calculated. The result could be used to calculate the spatial resolution of photoacoustic imaging system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820W (2009) https://doi.org/10.1117/12.835069
The vertical atmospheric sounding interferometer is based on the classical Michelson Interferometer mechanics. To keep
the uniformity of the speed and the alignment of the movable plane mirror, it introduces the referential optical path. As
the metrological standard, it is very important to get high-quality referential signals. Because of the complexity of the
interference system, the referential signals will degenerate when arriving at the laser detectors. In this paper, three factors
that impact the quality of the referential signals and countermeasures are presented. Firstly because the laser speckle is
not ideally proportioned and the laser beam is not ideally vertically reflected by the movable mirror, the laser speckle
swings with the movement of the movable mirror, resulting in the fluctuating of the power radiated on the laser detectors.
Secondly, when the initial angle between the fixed mirror and the movable mirror is too large, the modulation depth
ripples in a large scale with the small misalignment of the movable mirror. Lastly, the light reflected back to the
semiconductor laser will engender impact on the light source. By taking countermeasures, usable, accurate enough
referential laser signals are finally acquired.
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Xingchun Chu, Shanghong Zhao, Zhouliang Wu, Lei Shi, Shengbao Zhan, Yunxia Li, Lihua Ma
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820X (2009) https://doi.org/10.1117/12.834164
A new side pumping method based on the diffractive properties of a planar grating which is directly written into the
inner cladding of a double-clad fiber (DCF) is proposed. This technique assumes that the inner cladding of the DCF is
highly photosensitive and its diameter is large enough. Then a planar grating with a proper thickness can be written into
the inner cladding. The principles, characteristics and coupling efficiencies of the proposed scheme are described and
simulated by coupled wave theory. The simulating results show that the coupling efficiencies can achieve over 98% for
TE-, TM- and un-polarized incident pump lights simultaneously. And the average coupling efficiencies can still achieve
80% regardless of TE or TM polarization even when the pump wavelength ranges from 974 to 978nm and the incident
angle ranges from −0.8° to 0.8°. The fabrication tolerances of the planar grating and the leakage of pump powers for
multi-point side-pumping are also analyzed. The advantages of the proposed scheme include: (1) no risk of damaging the
DCF; (2) no index-matching optical adhesive; (3) high temperature sustainability; (4) simple, stable and compact. It
provides an effective way to scale the output power of DCF lasers or amplifiers to a high level.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820Y (2009) https://doi.org/10.1117/12.831988
A new experimental method is put forward for the influence of two laser spots on the direction deviation in four-quadrant
photoelectric detection for laser guidance. The experimental apparatus and findings are given. The results are: in two
cases of spot size, the curve of the relative center direction deviation vs. relative intensity difference of two laser spots;
the deviation error in each quadrant under the condition of relative intensity difference value less than 2%. It is
concluded that smaller relative intensity difference and larger spot size are beneficial to the decrease of the deviation
error. Based on the experiments a new scheme of twelve -quadrant photoelectric detection to eliminate the influence of
jamming spot on laser guidance is proposed: The twelve -quadrant photoelectric detector is composed of three
four-quadrant photoelectric detectors arrayed in left, middle and right side. When a jamming spot appears, its relative
position is judged by the circuit. When spots simultaneously appear in two quadrant photoelectric detectors, only the
signal of target spot is put into succeeding control circuits, so the influence of jamming spot is eliminated.
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Xia Ye, Yongkang Zhang, Hongbing Yao, Guilin Ding, Yanqun Tong, Yongfeng Gao, Shuisheng Yu, Lu Ding
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73820Z (2009) https://doi.org/10.1117/12.835001
When a short pulse of a Q-switched high-power laser hit surface of materials, laser energy would be absorbed rapidly,
thus producing explosive vaporization, and almost at the same time a high-pressure shock wave was induced, called laser
shock wave. This ultra-high pressure induced by high power laser had been applied in the fields of basic research and
engineering application such as inertial confined fusion, laser shock processing, etc. Influence of variable laser power
density on laser shock wave was studied in this paper. Influences of variation of laser wavelength and pulse duration on
laser shock waves were also discussed in laser shock processing. Piezoelectric Polyvinylidene Fluoride (PVDF)
transducer and TDS3052B Digital Oscilloscope were applied in our experiments to measure the piezoelectric wave of
PVDF and the corresponding stress wave induced by laser in real time. Differences and relations between laser-induced
shockwave and laser pulse in laser shock processing were researched according to the obtained waves, and the detailed
analyses of their causes were given based on the formation of laser-induced shock wave. The research results could have
important implications for a better understanding of characteristics of laser shock wave and further studies into the
interaction between high-power laser and materials.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738210 (2009) https://doi.org/10.1117/12.834093
With the development of semiconductor laser technology, laser proximity fuzes have been widely used in various kinds
of guided missiles and routine ammunitions. And its precision of ranging has a direct influence on the overall
performance of the system. This work employed Spartan III series FPGA chip from Xilinx company. Through phase
shifting the primary reference clock and ranging with four doubled-frequency clocks with each phase shiftings of 90
degree, the ranging precision can be improved obviously. The theoretical ranging error is 0.1875m and the result has
been proven by simulation with Modelsim. Valuable conclusions were drawn for improving the ranging precision of
laser fuze.
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Xinwei Wang, Yan Zhou, Songtao Fan, Yuliang Liu, Hongjun Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738211 (2009) https://doi.org/10.1117/12.836025
We have presented the Echo Broadening Effect of range-gated active imaging. It can respectively generate a head
signal part and a tail signal part both sides of the echo signal profile. Our research demonstrates that the head signal
and the tail signal impact the depth of view, detection range and imaging quality, especially the head signal. In order
to solve the problems, we establish a model of the echo broadening effect, and analyze the signal energy
characteristics and atmospheric backscatter. We have given the depth of view under the effect, verified it in
experiment, and found that the reasonable choosing of the illuminator laser pulse time and the camera gate time can
mange the effect to optimize range-gated imaging systems.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738212 (2009) https://doi.org/10.1117/12.834169
The optical channel models for airborne submarine laser communication are built and the received energy is discussed.
In this propagation channel, sea has the most important impact on the power attenuation. Applying the classical electron
scattering theory to the photo scattering effects in the sea, the transmission delay of underwater laser pulse is investigated
by small-angle approximation theory, caused by the scattering effects in the sea. To indicate the influences of the
seawater properties on the transmission delay, some interrelated curves are displayed. The multi-path time spreading of
signal pulse is studied. The waveform of received signals in receiver in submarine laser communication system is
analyzed and simulated by use of Monte Carlo simulation. The results deduced by using Monte Carlo coincide with that
simulated by using small-angle approximation theory.
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Bin Zhang, Lu-Hong Mao, Sheng Xie, Wei-Lian Guo, Yan Chen, Xin Yu, Xian-Jie Li, Li-Fang Qi
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738213 (2009) https://doi.org/10.1117/12.832158
Based on dynamics models of the electronic bi-stable behavior in a semiconductor ring laser and using the methods of
the modern nonlinear dynamics, the stability and bifuraction behavior in a semiconductor ring laser are analyzed and
calculated in this paper. The calculated results show that the ring laser can undergoes the Hopf bifurcation by changing
pump parameters which can lead the complex nonlinear movement such as limit cycle and Chaos. The effects of
backscatter parameters on the operation regions are also calculated The calculated results show that the change of
backscatter parameter can result different dynamics behaviors including bifurcation. At last the theoretical result is
compared with experiment. The device process and structure is described and the experiment result agree with our
theory.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738214 (2009) https://doi.org/10.1117/12.834823
A novel open loop Sagnac optical fiber sensing system for detecting AE(acoustic emission) has been proposed and
demonstrated. The fiber loop of the Sagnac interferometer was cut off and formed two fiber ports, they were bound and
made into the fiber probe. It was placed in the front of the reflector attached to the measured solid. The light from one
port was reflected by the reflector and injected into the other fiber port. On the basis of the output optical field
distribution function, the position of maximum reflected light intensity was theoretically analyzed. The best work region
between the fiber probe and the reflector was ascertained by the experiment. Phase modulation property of the optical
fiber sensor was discussed and the optimal working state was obtained by the computer simulation. The optical phase
was modulated by the vibration of the reflector generated by the AE. The AE signals were obtained though the
optoelectronic conversion, and the frequency of the AE were acquired by using Fourier transform. The experiment
results show that the system could be used to detect the ultrasonic waves that propagating on the surface of the solid. The
open loop Sagnac optical fiber interferometer sensor has potential for the structural integrity monitoring and NDT
applications.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738215 (2009) https://doi.org/10.1117/12.835034
In this paper, a new kind of long distance detection source-- hollow double-half
Gaussian laser beams is put forward. By use of modified Cassegrain optics system, we obtained
hollow beams with special light distribution-parallel hollow double-half Gaussian laser beams,
the intensity distribution of this kind of hollow beams is zero at all the hollow area and is
maximum at inner margin, so forms double half-Gaussian beams, and the inner and the outer
diameters of the hollow beams are controllable. The analytical equation of propagation and
transformation of the hollow laser beams in free space was deduced. The simulation shows that
the intensity exhibits three-dimensional trap distribution in the near-field, while the double
half-Gaussian hollow beams turns into solid laser beams when propagating a certain distance,
which shows the characteristic of self-focus. By use of the characteristic of self-focus of the
double half-Gaussian hollow beams, we can realized the self-gating long distance detection to the
small object even if in the condition of lower laser power. The technology will be applied broadly
in the near years.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738216 (2009) https://doi.org/10.1117/12.834854
The availability of reliable optical sensor technology provides opportunities to better characterize and control plasma
etching processes in real time, they could play a important role in endpoint detection, fault diagnostics and processes
feedback control and so on. The optical emission spectroscopy (OES) method becomes deficient in the case of deep
submicrometer gate etching. In the newly developed high density inductively coupled plasma (HD-ICP) etching system,
Interferometry endpoint (IEP) is introduced to get the EPD. The IEP fringe count algorithm is investigated to predict the
end point, and then its signal is used to control etching rate and to call end point with OES signal in over etching (OE)
processes step. The experiment results show that IEP together with OES provide extra process control margin for
advanced device with thinner gate oxide.
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Lei Shi, Shanghong Zhao, Xingchun Chu, Kanmin Yu, Lihua Ma, Shengbao Zhan, Yunxia Li
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738217 (2009) https://doi.org/10.1117/12.836563
Based on Navier-Stokes equations, numerical simulations of air-breathing mode laser propulsion by nanosecond laser
pulse are carried out. An analytical model of the thruster's inner flow involving the simple processing of the ignition
zone is established. The evolvement of the laser sustained plasma shockwaves is systemic analyzed; also the effects of
pulse energy and thruster's structure such as focal length, scale and open angle on propulsion performance are
researched. The simulated results show that the focal length dominates among the structural factors of thruster in the
propulsion by nanosecond laser pulse. The larger focal length leads to better propulsion performance. It is also evident
that for single pulse propulsion, nanosecond laser pulse is better than microsecond laser pulse, the momentum coupling
efficient achieved by the former is 2~5 times of the latter's, which is highly agree with the existing experimental results.
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Guolong Du, Guiqiu Li, Shengzhi Zhao, Jing An, Ming Li, Jian Liang, Tao Li, Wei Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738218 (2009) https://doi.org/10.1117/12.835555
Optical second-harmonic generation (SHG) in the form of Cerenkov radiation is analyzed by directly resolving the wave
equations. A simple general solution has been obtained which expresses the SHG efficiency in terms of waveguide
parameters. Numerical examples are plotted for ion-implanted Lithium Niobate (LiNbO3) planar waveguide.
Keywords: LiNbO3, TM mode, Cerenkov SHG, ion-implantation, planar waveguide.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738219 (2009) https://doi.org/10.1117/12.836270
The in-situ chemical detection in deep sea is very important for mineral resources exploitation. Laser Raman
Spectroscopy as a powerful tool for chemical analysis has been used in deep sea detection recently. It was found that
the fluorescence always exists as the background on Raman spectra detecting in ocean. It is apparent that the
fluorescence background could be decrease effectively using near infrared wavelength as excitation source. While near
infrared laser has few application underwater due to the absorption of water in this wavelength range. In this paper, a
785nm Raman spectrometer was used to evaluate the near infrared laser Raman spectroscopy for underwater application.
It was found that the Raman shift of SO42- at 981cm-1 can be easily detected from Qingdao near shore sea water samples
without sever fluorescence background. With mixed solution of SO42- and HCO3
-, the detection limit achieved for
SO42- at 981cm-1 and HCO3
- at 1017cm-1 was obtained by 785nm compact Raman spectrometer to be 0.00625mol/l and
0.025mol/l with 10s integration time respectively. The obtained results proved the feasibility of near infrared laser
Raman underwater detection.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821A (2009) https://doi.org/10.1117/12.832651
A single mirror 2D laser scanner is designed, produced and tested in the paper. The mirror of the scanner is suspended on
a compact cross blade flexure and driven by four voice coil actuators. The voice coil actuators designed specially can
output strong driving force and have sufficient large gap for mirror's deflection. An in-house ingenious deflection angle
detecting system based on a 2D position sensitive detector provides feedback to enable two-axis closed-loop scanning.
Details of the voice coil actuators design, the mechanical structure design and deflection angle detecting system as well
as the control-loop implementation are described. Test results shows that the mechanical deflection angles in both
azimuth and elevation are about ±5°, and the closed-loop bandwidth is 350Hz. The diameter of the mirror is 40mm, and
the diameter of laser beam can reach 35mm when mechanical scanning angle is 5°. A 2D scanning is realized by the
scanner deflecting in two orthogonal axes. The vertical scanning frequency is 10Hz, and the scanning wave is triangle
wave. At the same time, the horizontal scanning frequency is 80Hz, and the scanning wave is sine wave.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821B (2009) https://doi.org/10.1117/12.835110
Fluorescence spectroscopy and fluorescence imaging diagnosis of malignant lesions provides us with a new method to
diagnose diseases in precancerous stage. Early diagnosis of disease has significant importance in cancer treatment,
because most cancers can be cured well in precancerous, especially when the diffusion of cancer is limited in a restricted
region. In this study, Golden hamster models were applied to 5% 9, 10 dimethyl-1, 2-benzanthracene (DMBA) to induce
hamster buccal cheek pouch carcinoma three times a week. Rose Bengal, which has been used in clinican for years and
avoids visible side-effect to human was chosen as photosensitizer. 405 nm blue LED was used to induce the fluorescence
of photosensitizer. After topical application of photosensitizer, characteristic red emission fluorescence peak was
observed around 600nm. Similar, normal oral cavity has special luminescence around 480nm.
Fluorescence spectroscopy technology is based on analysing emission peaks of photosensitizer in the areas of oral
carcinoma, moreover, red-to-green (IR/IG) intensity ratio is also applied as a diagnostic algorithm. A CCD which is
connected with a computer is used to take pictures at carcinoma areas through different filters. Fluorescence images
from normal hamster buccal cheek pouch are compared with those from carcinogen-induced models of carcinoma, and
morphological differences between normal and lesion tissue can be distinguished. The pictures are analyzed by Matlab
and shown on the screen of computer.
This paper demonstrates that Rose Bengal could be used as photosensitizer to detect oral carcinoma, and blue LED as
excitation source could not only have a good effect to diagnose oral carcinoma, but also decrease cost greatly.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821C (2009) https://doi.org/10.1117/12.834102
The AGWN model, based on the atmospheric attenuation and turbulence effect is present. In the paper, a robust image
watermark technology is proposed based on extended set partitioning in hierarchical trees algorithm (ESPIHT) and low
density Parity check codes (LDPC). The Watermarking Algorithm is applied in the free space optical communication
(FSO) by Joint Source-Channel Coding (JSCC), and simulated in BPSK modulation over AWGN channel and different
level error correction channel coding. The results of simulation show that the presented algorithm is effective and robust
to common image processing operations and some distortions such as cropping, pinching, pixel-shifting and so on. And
it has strong error correction performance in burst errors and random errors, so it is appropriate for complicated
environment of FSO.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821D (2009) https://doi.org/10.1117/12.830923
An improved algorithm of 2-D Empirical Mode Decomposition (EMD) in image processing has been presented. It
contains selecting extrema of the pixels and interpolation of them in the course of EMD, A variance phenomenon has
been discovered in the interpolation of boundary pixels. Delaunay Triangulation has been used to partition the selected
extrema, a pixel that not contained in the Delaunay polygon can be processed through symmetry principle, It can restrain
the variance phenomenon that appeared in the cubic spline interpolation. An image has been processed with the
improved algorithm, The calculation result of standard deviation between the original image and the reconstructed image
is 6.667×10-6 . A slight fluctuation can be seen from the calculation result. The reconstructed image is consistent with the
original image. It demonstrates that the improved algorithm been presented is accurate and feasible. The method of EMD
is used in image compression and de-noising more and more popular, therefore, the improved algorithm in the paper will
be useful in the course of calculation speed enhancement of image processing based on EMD.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821E (2009) https://doi.org/10.1117/12.835003
In this work, an absolute distance measurement method based on the self-mixing interference is presented. The
principles of the method used three-mirror cavity equivalent model are studied in this paper, and the
mathematical model is given. Wavelength modulation of the laser beam is obtained by saw-tooth modulating the
infection current of the laser diode. Absolute distance of the external target is determined by Fourier analysis
method. The frequency of signal from PD is linearly dependent on absolute distance, but also affected by
temperature and fluctuation of current source. A dual-path method which uses the reference technique for
absolute distance measurement has been proposed. The theoretical analysis shows that the method can eliminate
errors resulting from distance-independent variations in the setup. Accuracy and stability can be improved.
Simulated results show that a resolution of ±0.2mm can be achieved for absolute distance ranging from 250mm to
500mm. In the same measurement range, the resolution we obtained is better than other absolute distance
measurement system proposed base on self-mixing interference.
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Ming Ling, Guang-yong Jin, Xue-chun Tan, Zhi-chao Wu, Zhu Liang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821F (2009) https://doi.org/10.1117/12.834586
A novel LD side-pumped Nd:YAG Q-switched solid-state laser, which made use of the special pumping strcture with
conductive cooling instead of water cooling, was investigated.After selecting an appropriate length and diameter of
Nd:YAG laser crystal rod and using three groups of laser diode centimeter bar which was composed by 12 laser diodes
and uniformly arranged according to the angle of 120°,side-pumping structure of laser was accomplished.Adopting
plano-concave resonator ,mending double end face of laser crystal and designing heat-stability resonator made the
resonator steadily oscillate.Laser crystal rod which was tight fastened by copper net was conductively cooled and
radiation block was furnished on the external of copper net for increasing the radiation capacity.High reflection gold
film was plated on the cooling wall in the opposite way of pumping light, so that the laser crystal was uniformly pumped
and the laser with low order mode output.Making the use of pillar lens focus and ray trace computing, reasonable
parameters were caculated to couple pumping light to laser with high-efficiency.It was the electrooptic Q-switched which
was made to be micro-integration eliminating voltage by KD*P crystal that improved the ratio between acting and
unacting.Inner heat radiated from laser in good time with TE cooler and the laser ran at constant temperature with water
cooling when the big external heat sink emanated a steady heat to periphery. Experiments revealed that the syetem
pumping efficiency riseed by 18% and the laser threshold energy was 192 mJ under the condition of this novel
pumping structure. The low mode output of 10~12ns pulse width and the maximum output energy of 98 mJ was
achieved with an incident pump energy of 720 mJ in 1064nm.The optical-to-optical conversion efficiency was up to 13.
6 %,and the power instability in 24 h was better than ±1. 7 %.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821G (2009) https://doi.org/10.1117/12.833406
Generally speaking there are two orthogonal signals used in single-frequency laser interferometer for
differentiating direction and electronic subdivision. However there usually exist three errors with the
interferential signals: zero offsets error, unequal amplitude error and quadrature phase shift error. These three
errors have a serious impact on subdivision precision. Based on Heydemann error compensation algorithm, it
is proposed to achieve compensation of the three errors. Due to complicated operation of the Heydemann
mode, a improved arithmetic is advanced to decrease the calculating time effectively in accordance with the
special characteristic that only one item of data will be changed in each fitting algorithm operation. Then a
real-time and dynamic compensatory circuit is designed. Taking microchip MSP430 as the core of hardware
system, two input signals with the three errors are turned into digital quantity by the AD7862. After data
processing in line with improved arithmetic, two ideal signals without errors are output by the AD7225. At the
same time two original signals are turned into relevant square wave and imported to the differentiating
direction circuit. The impulse exported from the distinguishing direction circuit is counted by the timer of the
microchip. According to the number of the pulse and the soft subdivision the final result is showed by LED.
The arithmetic and the circuit are adopted to test the capability of a laser interferometer with 8 times optical
path difference and the measuring accuracy of 12-14nm is achieved.
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HuanHuan Liu, XiaoDong Zeng, ChangQing Cao, ZheJun Feng, Chao Fu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821H (2009) https://doi.org/10.1117/12.836537
The diffraction limit of laser is smaller than microwave's for its shorter wavelength. Higher spatial resolution will be
achieved when laser is applied to the synthetic-aperture radar, called synthetic-aperture laser radar (SAL). Just because
of many advantages, in recent years the research on SAL is becoming a hotspot. One of key techniques of SAL is
heterodyne detection of signals by means of linear frequency modulation pulse compression (LFM-PC); this paper
introduces an experiment based on heterodyne detection with an acousto-optic frequency shifter (AOFS) in our
laboratory. Detailed discussion about AOFS is presented. We find that the acousto-optic modulator can considerably
influence the transmitted light beam. In particular, when the width of laser beam is larger than the effective width of
acousto-optic cell, the transverse distribution of scattering light intensity is inhomogeneous, which will decrease the
signal-to-noise ratio of the heterodyne detection. This paper discusses the coupled partial difference equations
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Li-li Wang, Xiao-dong Zeng, Zhe-jun Feng, Chang-qing Cao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821I (2009) https://doi.org/10.1117/12.836540
When remote objects are detected by use of SAL, weak echo signal is easy to be interfered by noises. To obtain high
receiving performance, the amplifier and signal processing system should be carefully designed. In this paper, the circuit
consisting of the microwave filter, the pre-amplifier and the main amplier is designed under the condition of photodiode
impedance matching. The major noises of PIN photo diode are analyzed and a low noise pre-amplifier circuit is
designed,which can improve the signal to noise ratio ( SNR ) effectively. The noises are filtered by a microwave filter.
The circuit self-excited owing to high frequency operating is also taken into account. Some measures that the device is
reasonably selected and the circuit is legitimately designed are implemented. The anti-interference of the circuit and the
ability of restraining self-excited are improved by shielding box etc. Experimental results indicate that the receiving
circuit has small volume and high reliability with high performance.
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Xiaoyan Zhao, Xiaodong Zeng, Changqing Cao, Zhejun Feng, Chao Fu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821J (2009) https://doi.org/10.1117/12.836538
Heterodyne detection based on the inverse synthetic aperture ladar (ISAL) can obtain useful information such as
phase and amplitude and frequency of the moving target. Through analysis of these information, we can conclude
the exact appearance, orientation and other characteristic about the target. However, the heterodyne detection is
usually difficult to accomplish. The difficulties lie in two main aspects: the first one is that the wavefront of returned
signal wave and local-oscillator wave are misaligned. The second one is that the random phase delay of the returned
wave. In this paper, we analyze systematically the principle and effect of heterodyne detection such as separation
angle and spot size. Then a useful conclusion is presented to state the exist problem about match between signal
wave and local-oscillator field.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821K (2009) https://doi.org/10.1117/12.832382
Solar-Blind Ultraviolet Optics Communication is a new type of communication system in atmosphere optics
communication fields. Its excellent performances such as safety, 24-hour service, anti-interference, non-line-of-sight,
make it different from infrared optics communication. Hence, the solar-blind ultraviolet optics communication
gratified the need of special and confidential communication in army. The atmosphere propagation characteristics of
the solar-blind ultraviolet is still a difficulty of the communication system. In order to solve this problem, this paper
majored on the influences of the solar-blind ultraviolet propagation by the absorption of ozone, the scattering of
atmospheric molecule and aerosol.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821L (2009) https://doi.org/10.1117/12.834945
Gaseous ammonia is the most abundant alkaline trace gas in the atmosphere. As ammonia plays an
important role in acid deposition and aerosol formation, it influences the regional air quality and
atmospheric visibility. TDLAS (Tunable Diode Laser Absorption Spectroscopy)is a method to obtain the
spectroscopy of single molecule absorption line in the characteristic absorption spectrum region as the
characteristic of the distributed feed back (DFB) diode laser with narrow linewidth and tunability, which
makes it possible to detect trace-gas qualitatively or quantificationally. The NH3 in-situ monitoring
instrument based on TDLAS and long open path technology have been developed combining with
wavelength modulation and harmonic detection techniques to obtain the necessary detection sensitivity.
This instrument has been used to measure atmospheric NH3 concentration at an urban site near Beijing
National Stadium from July to October in 2008, especially in the period of Beijing Olympics and
Paralympics. The continuously monitoring results show that the atmospheric NH3 concentration variation
has an obvious diurnal periodicity in the urban of Beijing. First of all, the general diurnal variation rule is
the concentration decreased to the minimum in the daytime, and then increased to the maximum at
night. Moreover, the NH3 peak concentration decreased obviously at the beginning of the Beijing Olympics
then it kept descending during the Paralympics. The obtained maximum of NH3 is between 20.31μg/m3~
48.54μg/m3 with the daily average concentration between 12.6μg/m3~27.5μg/m3. During these three
months, Air Quality Assurance Scheme for the Olympics (AQASO) was implemented through the joint
actions of Beijing Municipal Government and the five neighboring provinces/municipalities in north China.
The measures such as auto restriction and plant ejection-decreasing are carried out in Beijing. In conclusion,
the open-path TDLAS instrument is suitable for atmospheric trace gases detection on-line with its high
resolution, high sensitivity, rapid response time without gas sampling. Also correlation studies have
verified the positive effects of measures taken for improving the air quality including restricting ammonia
formation.
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Zhao-yun Zhang, Yang Gao, Xing-hai Zhao, Xiang Zhao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821M (2009) https://doi.org/10.1117/12.832329
Laser output power and frequency are modulated when the optical beam is back-scattered into the active cavity. By
signal processing, the Doppler frequency can be acquired, and the target's velocity can be calculated. Based on these
properties, an interferometry velocity sensor can be designed. In order to know whether the self-mixing laser diode
velocimeter is suitable for high speed (km/s) scene, the self-mixing laser diode velocimeter's maximum measurable
velocity (MMV) is analyzed. Based on the three-mirror cavity model, relations of the laser output power's frequency
fluctuations and Doppler frequency are acquired. External optical feedback is regarded as laser's small-signal
modulation by the Doppler frequency. From rate equations of the carrier density and the photon density, following
conclusions is acquired: self-mixing laser diode velocimeter's MMV is restricted by laser's relaxation resonant
frequency in principle; self-mixing laser diode velocimeter's MMV goes up to kilometers per second theoretically. The
result is available to use the self-mixing technique to develop high performance, small overall dimensions and low cast
instruments to measure high speed.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821N (2009) https://doi.org/10.1117/12.835275
The physical property parameters of laser crystal in solid state lasers vary strongly with temperature, which will
intensely affect the thermal effects of high power LD pumping solid state laser (DPL). In this study, by correcting the
intensity distribution of the laser beam emitted from the pumping source of laser diodes, a heat transmission model for
the laser crystal of a side-pumping geometry with a triangle uniform distribution was established. The temperature and
stress distribution are calculated and compared using finite element method under two different conditions, which
thermal conductivity, heat capacity and coefficient of thermal expansion of the laser crystal media vary with the
temperature, and these physical property parameters are constant. The results show that temperature at the center of laser
crystal media will further increase, and there will produce an additional stress except for thermal stress due to the
temperature gradient at the radial direction in the laser crystal, which result in more serious thermal effects. This study
provides a more visual and accurate reference model for the design and optimization of high power laser diode side
pumped solid state lasers.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821O (2009) https://doi.org/10.1117/12.835481
Cooperative effect radiation loss of optical pump solid laser was investigated deeply. Using Maxwell-Bloch equation the
characteristic and cause of coherent spontaneous were discussed .By laser rate equation, the expression of upper energy
level lifetime shortening due to the cooperative effect radiation was given. The influence of cooperative effect for laser
threshold and the loss were analyzed. Through the experiment, the relation of coherent spontaneous radiation intensity
and direction with reversal population and the power of optical pump was obtained.
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Xue-chun Tan, Guang-yong Jin, Zhi-chao Wu, Ming Ling, Zhu Liang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821P (2009) https://doi.org/10.1117/12.835353
The development of range-imaging devices is motivated by various ground and space applications. Tasks in space
missions include docking, rendezvous, manipulating robotic arms, landing and autonomous rover applications, sample
identification and surface mapping. The ground applications include the guidance of vehicles, robotic and manipulator
arms, and other autonomous or teleoperated machines, as well as surface or construction model generation. Without the
scanner devices, scannerless imaging lidars have the characteristic of high frame rate, wide field of view and high
reliability,which can be successful used in terminal guidance. Diode pumped laser radar with high repetition rate is
studied in this paper. A bistatic system is set up and a high speed signal processor for the system is researched. In a
conceptual sense, the imaging lidar has two parts, a transmitter and a receiver. Their field of views overlap throughout
the measuring range.The imaging lidar operates as follows. Based on principle of pulsed time-of-flight (TOF) laser range
finding, the solid-state laser diode-pumped laser produces short laser pulses, which though the expanded lens, then
reach the target. The back reflected light is collected with a receiver lens and fed through optical fibres to discrete
avalanche photo diodes (APDs). When a received pulse is detected by the comparator a time to digital converter (TDC)
stops counting and a time interval, corresponding to the range, is produced. The precision of a single measurement is
about ±4.0cm, but better precision is achieved by averaging. Information about the reflectivity of the target is gathered
by recording the amplitude of the received pulse. Range images with the lidar prototype were taken indoors, the
measuring distance was about 14m.
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Sanhong Wang, Yonghui Liang, Qifeng Yu, Xiaojun Xu, Haotong Ma
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821Q (2009) https://doi.org/10.1117/12.835389
Thermal aberrations in high-power solid-state lasers degrade the beam quality and cause diffraction losses that reduce the
output power. Adaptive optics system can be used to compensate for the wavefront distortions in real time to clean up
the beam. But the conventional adaptive optics system based on wavefront sensing can't work well with the high-power
laser beam cleanup because of the presence of branch points in the phase and the amplitude scintillation. However the
other kind of adaptive optics system based on model-free optimization of a scalar beam-quality metric provides an
attractive approach to perform the beam cleanup in smaller packages. Such an adaptive optics system with iteration rate
of 100 Hz was built up. In this system a stochastic parallel gradient descent (SPGD) algorithm is implemented in a
computer to control a deformable mirror for wavefront correction. Beam cleanup experiments with the SPGD AO system
were conducted. The high-power laser beam was simulated by transmitting a low-power high-quality laser beam through
an Nd: YAG-crystal power amplifier. The thermal aberrations of the beam could be changed by adjusting the pumping
current of the power amplifier. The experimental results on the convergence and stability of this adaptive system for
various conditions of dynamic aberrations are presented.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821R (2009) https://doi.org/10.1117/12.835945
The aim of this paper is to explore a high-precision, a wide range of a frequency discrimination technique, and to
study the application of this technique in the optical air data system (MOADS). To overcome the traditional
equipment's shortcomings of short velocity detecting range such as pilot static tubes and wind wane, this technique
can provide precision aviation data for various aerocrafts , without influencing pneumatic shape and performance of
aerocraft.
A tunable dual channel Fabry-Perot interferometer is used as a frequency discriminator in an airborne wind lidar
system. This new frequency discriminator has been proposed to overcome the exiting frequency discriminator
shortcoming. By adjusting the cavity length of interferometer, the speed of aerocraft can be detected and cut into
several dynamic range. By this way, the Doppler wind lidar system can detect atmospheric parameters at the
meantime, such as speed of aerocraft and temperature of atmosphere around the aerocraft, by analyzing the
information of Rayleigh backscattering light. There are three main contribution in this paper: the first is discussing
the basic theory of MOADS, calculational method and mathematic model of relative wind velocity between aircraft
and wind are put forward.; the second is the parameter optimization of the dual-channel Fabry-Perot interferometer
and the structure design of the interferometer; the third is the simulation of the performance and the accuracy of this
system. Theory analysis and simulation results show this method is reasonable and practical.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821S (2009) https://doi.org/10.1117/12.834892
The identification of tumor is important for the diagnosis of early cancer. Optical reflectance spectrum of human tissue
could reveal the characteristics of the tissue that helps medical diagnosis. Multispectral imaging techniques have been
widely used for the application of digital recording. In this article we developed a multispectral imaging system with a
monochrome CCD, five optical filters including conventional RGB filters and two narrow band filters, light source and
imaging processor. We propose a method to reconstruct the reflectance spectrum using a selective combination of
spectral estimation technique. With the reconstructed spectrum, we can form the image of the object in certain
wavelength that is not in the range of any of the wavelengths corresponding to the above filters. The imaging
constructing speed of multispectral imaging system is limited by CCD speed. In order to reconstruct the reflectance
spectrum in real-time, the number of the filters involved in the reconstruction should be as less as possible. In the
experiment, we investigate the relationship between the number of the filter channels and the estimation error (RMSE)..
To minimize the estimation error, we use Weiner estimation to choose the best combination of filter channels for certain
wavelength. Using the proposed method, we can achieve high accuracy of image reconstruction with limited number of
filter channels in real time.
In this paper, the multispectral imaging system setup is briefly introduced, and the method of reconstructing the
reflectance spectrum is described.
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Zhaoxiang Lin, Liang Chang, Jie Li, Yelin Liu, Linmei Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821T (2009) https://doi.org/10.1117/12.835687
This paper reports studies on metals in the liquid by laser-induced breakdown spectroscopy in order to detection of
heavy metals in industrial wastewater. A measuring device by LIBS has been established which including the Nd:YAG
laser, Echelle spectrograph, intensified charge-coupled device (ICCD) and liquid jet. The characteristic spectral lines of
twelve metals in actual industrial wastewater from a certain nonferrous metals company were analyzed using LIBS. The
calibration curves of the metals in liquid were acquired by the experiment and the linear correlation coefficients were
high. The detection limits of metals obtained from the liquid were low, especially for the Ca, Cu, K, Mg, Mn and Na.
The results show that the measuring system can be applied in the on-line, rapid detection of heavy metals in industrial
wastewater, and it has wide range of applications.
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Xian-an Dou, Chuang-xin Zhang, Xiao-quan Sun, Li Shao, Zhong-cheng Tong
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821U (2009) https://doi.org/10.1117/12.835689
In order to study the atmospheric turbulence's influence on active laser reconnaissance, a theoretical model of cat-eye
system illuminated by Gaussian-beam which propagates through atmospheric turbulence over a long distance was
constructed. The mean irradiance and the scintillation index were calculated under the Rytov approximation. The
theoretical analysis and numerical simulation results indicate that the mean irradiance and scintillation index of the
active laser reconnaissance echo influenced by atmospheric turbulence are both increased near the optical axis.
Experiment was carried out to validate the theoretical analysis results and the experimental results are shown to be in
good agreement with the theoretical predictions.
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Yun-lei Wang, Ke-fei Song, Wei-lai Zhang, Jun-ling Li
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821V (2009) https://doi.org/10.1117/12.835224
In the device, a He-Ne laser of flash frequency 1-20 Hz was adopted as exciting light source, and three key technical
problems have been solved successfully in order to enhance the detecting sensitivity and measuring stability of the
device for time-resolved fluorimmunoassays(TRFIA)[1]. The first one is to design optimum exciting optical system, so
that the exciting light beam excite the sample most effectively. The second one is to have a project spectrum filter which
can reduce the affection of the background light to the photomultiplier tube and also ensure influence of the stray light
and mixed diffusion light to the sample fluorescence to the least, the sample fluorescence through the integrating sphere
and come to the grating monochromator, The right wavelength will be chosed through changing the angle of incidence of
the grating monochromator. The third one is to simulate the principle of sample averaging of BOXCAR averager. In the
device, SCM was used as primary controller and CPLD was used as timing controller. Through the preparation process,
signal-to-noise ratio(SNR) will be improved, also adjust delay time, ampling frequency and sampling number arbitrarily.
By testing, the sensitivity is 10-12mol/L(substance marked by Eu3+), examination repeat is ≤2.5%, examination linearity
is from 10-8mol/L to 10-12mol/L, correlation coefficient is 99.98%(p≤0.01). The instrument is advanced for ultrasensitive
detection of antigen and antibody , and solve the tumor, genetic variation, the virus protein detection.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821W (2009) https://doi.org/10.1117/12.835485
Based on the theory of the conical refraction, the hollow conical laser will appear at the internal of the biaxial crystal
when laser traveling along one of the axis of the biaxial crystal. The hollow conical laser is different from the solid laser;
all of its energy is disturbing on the cone that is similarly the funnel. The study of the produce and control of the hollow
conical laser will provide the theoretical and technique basis for its application. In this paper, Based on the matter
equation of anisotropies and the propagation law of light in the biaxial crystal, the production of the conical laser was
theoretically analyzed and calculated in detail, and the cone angle equation of the hollow conical refraction was obtained,
which provided the control and modulation of hollow conical laser with theoretical bases. The cone angle of the conical
laser was adjusted by changing the convergence angle of the incidence laser; the all-beam, large-angle and dynamic
laser scan was realized by controlling emergent conical laser with varifocal system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821X (2009) https://doi.org/10.1117/12.834905
The study of the spectral switches has been extended to the off-axis regime within the framework
of the paraxial approximation, and the main attention is focused on the influence of the off-axis parameters
and incident angles on the behavior of the spectral switches. It is shown the critical position uc, spectral
minimum Smin and transition height Δ of the spectral switch depend on the off-axis parameters Δu and incident
angles φ. By a suitable choice of system parameters, Smin, Δ and zc of the spectral switch can be variable.
Therefore, this kind of spectral changes might find some interesting applications in spectrum-selective
interconnects. The on-axis Gaussian beams are treated as a special case of the general result.
Keywords: modern optics, aperture diffraction, spectral switch, off-axis Gaussian beam
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821Y (2009) https://doi.org/10.1117/12.835036
The polarization characteristic of laser backscattering from randomly rough surfaces is studied theoretically and
experimentally in this paper. The effect of multiple scattering from rough surfaces is analyzed. The equation for the
backscattering coefficient and the polarization of Gaussian rough surfaces are derived and the simulation is conducted
under several certain conditions. The polarization characteristics of different materials with different shapes are
measured. The experimental results and the simulated numerical values are compared and analyzed in detail.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73821Z (2009) https://doi.org/10.1117/12.835536
In this paper, the impact of factors on frequency conversion efficiency has analyzed departing from the theoretical
formula of frequency doubling frequency efficiency. The results of analyzing show that the frequency multiplication
efficiency closely to be not only related to the fundamental frequency laser parameter, but also influenced by several
factors such as crystal type, crystal length and so forth. Because of the needs of high conversion efficiency of doubling
frequency, the fundamental frequency laser parameter, the crystal type and the crystal length must be determined
reasonably to achieve the optimum parameter between fundamental wave peak power density and phase mismatch factor.
To compare with the conclusion mentioned above, an experimental device was established on 266nm quadrupler UV
laser and 10mJ UV laser which quadruple conversion efficiency 15.5% was achieved in the condition of fundamental
frequency single pulse energy 60mJ, the divergence angle under the beam quality M 2=2, pulse width 10ns.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738220 (2009) https://doi.org/10.1117/12.835257
Hydrogen Sulfide, with the character of erosion and strong toxicity, is a kind of associated
gas of nature gas. How to measure and monitor the hydrogen sulfide concentration becomes an
important issue to be solved in nature gas transfer-process. Online measurement for the hydrogen
sulfide concentration before the desulphurization remains very difficult in Bonan gas gathering station
of SINOPEC Shengli Oil Field (SOF).TDL(Tunable Diode Laser) can relative easily select the
absorption line of the detecting gas without the interference from other gas thus make the rapid and
accurate hydrogen sulfide measurement a possible. In this paper, a hydrogen sulfide measurement
system is designed and then be carried out in Bonan gas gathering station of (SOF) .The implemented
experiments showed the system effectively solved some problems such as overfall, temperature and
pressure. After comparing the hydrogen sulfide online detection sensor of the TDLAS industry with the
long hydrogen sulfide detection tube, the linear fitted relationship with the correlation coefficient of
99.96% between them was attained. In order to meet the requests of industrial field anti-explosion, the
open-path optical coupling technology was performed in china for the first time. All the results
demonstrate that the system will be put into use and enjoy a high application in the near future.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738221 (2009) https://doi.org/10.1117/12.835529
Aiming to the noise effect on weak signal extraction in the laser off-axis scattering detection, the signal processing
technique, which applies the stochastic resonance that when the stochastic resonance among input signal, noise and
nonlinear system is reached the output signal noise rate (SNR) is improved by converting the power of noise into the
signal, is put forward. On the adaptive stochastic resonance theory, the new algorithm combining the genetics algorithm
and adaptive resonance algorithm, which is optimized by applying niche technique and 'cross generational elitist
selection' strategy. Meanwhile, the concrete realization description and stimulation are made out. It shows that the weak
can be well detected from the low SNR circumstance, and the new method by that in the laser off-axis scattering
detection the noise effect on weak signal extraction is weakened, is found. The method is promising in the applications
such as laser alarm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738222 (2009) https://doi.org/10.1117/12.834299
In terminal optical system of the ICF (inertial confinement fusion) , the large caliber (310mm*310mm) beam sampling
grating (BSG) is used to confirm the energy of the main laser by measuring the -1st transmission diffractive light
intensity of the main laser beam.The characteristics of BSG's energy response directly affects the measurement
accuracy. The characteristic of BSG's energy response has been studied in this paper based on the actual intensity
distribution of the ultra-high energy laser beam and the spatial distribution model of diffractive efficiency of BSG.
BSG's energy response affected by its uniformity of the diffractive efficiency has been analysised, too. The results
indicate that the spatial distribution of diffractive efficiency of BSG is directly related to the energe response
characteristics and the uniformity of BSG's diffractive efficiency has an impact on the accuracy of the sampling of
energy.This research provides a theoretical basis for evaluating the high-energy sampling device's energy response
characteristic in ultra-high energy diagnosis. The technical indicator with the uniformity of BSG's diffractive efficiency
has been attained and these results are use for the fabrication of the beam sampling gratings in practice.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738223 (2009) https://doi.org/10.1117/12.830690
The optical Pulse Position Modulation (PPM) is applied widely in Free Space Optical communication (FSO) with the
low average power and the high peak power. The transmitted PPM information depends on the location of the coming
optical pulse signals in fixed period. Both receiver and transmitter should been kept in time slot synchronization and
frame synchronization in demodulation. Because the channel is very complex, the received optical pulse width will be
stretched randomly. We design and realize one digital PPM modulation receiver with high sensitivity using the
technology of PMT, A/D converter, and DSP. It is suitable to the total digital optical receiver with random time slots and
random pulse width. The paper will mainly discuss the realization of the soft demodulation behind A/D converter. The
key of PPM digital soft modulation is the establishment of the synchronization that involves the segment
synchronization, the fame synchronization and the bit synchronization. The synchronization can be obtained by seeking
for the frame head in data frames. Based on the estimation of received waveform characteristics, we adopt a matched
filter without the best factors firstly. Thereafter, their errors will be self-adapted while finding the synchronization head.
Considering the real-time need, we choose the reduced mode of maximum likelihood function judgment finally. In the
experiments, results with high sensitivity and low bit error rate have been achieved.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738224 (2009) https://doi.org/10.1117/12.831208
Through a Nd:YAG pulse laser of 1064nm wavelength, a multichannel grating spectrometer, and seven CCD detectors,
the plasma emission spectrum of the 200 - 980nm wavelength rang were simultaneously observed. First, we studied the
influences of some factors like laser energy and measurement time delays on emission intensity of plasma. By
experiments, we found that the unusual phenomenon that the emission intensity of plasma is possibly stronger when laser
energy is smaller for steel samples. However, this stronger intensity obtained under smaller laser energy is not suitable to
quantitative analysis because of poorer repetition. Second, we determined the optimal experimental parameters and
quantitatively analyzed the concentrations of the element Mn, Ni, Cr, V, Ti and Cu in some steel samples under the
optimal experimental parameters. The calibration curves of these elements were built, and good linearity was obtained.
The average relative errors of the quantitative results of these elements are between 13.31% and 4.54%. Consequently,
LIBS can be used for quantitative analysis for steel samples; however, the accuracy of the quantitative results still needs
to be improved.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738225 (2009) https://doi.org/10.1117/12.835986
An ultraviolet Raman lidar system at 354.7nm laser wavelength has been developed to measure
the elastic scattering signal and the vibrational Raman scattering signal of N2 and H2O for
fine-detection of atmospheric humidity profile. A newly spectroscopic filter structured with a
high-spectral-resolution grating and two narrow band mirrors are used to separate those
backscattering signals finely. The density of humidity is derived from the vibrational Raman
scattering signal of N2 and H2O, the relative humidity profile is obtained combining with the
temperature profile taken simultaneously by Raman temperature lidar. Some preliminary
experiments have been carried out in nighttime at Xi'an area, the wator vapor mixture ratio
vertical profile is analyzed. The experiments results indicate that a measurement error of the
relative humidity less than 10% is obtained within the atmospheric boundary layer under the
condition of laser energy of 300mJ and observation time of 10min.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738226 (2009) https://doi.org/10.1117/12.835308
For lidar probing technique, the lidar ratio is one of key factors which impact the precision of lidar detection. Lidar ratio depends on
not only incident laser wavelength but also aerosol size distribution and complex refractive index, and its value is between 0 and 90sr.
However, lidar ratio was simply suggested as a fixed value of 50 sr for a long time, which means that the atmospheric aerosol size
distribution and chemical compositions do not change with temporal and special variableness. In order to improve the detection
precision of lidar extinction profile, it is necessary to study the changes of lidar ratio. For the measurements with an upward-looking
monostatic lidar system, due to the change of the relative humidity along the measurement path, the lidar ratio may differ considerably
from an assumed constant range-independent value. One of the objectives of this study is to quantify this variability for different
aerosol types by numerical methods, and we will give out multi-type aerosol lidar ratios, such as continental clean, continental average,
continental polluted, urban, desert, maritime clean maritime polluted and maritime tropic et al. The results will provide valuable
references for the lidar development and the derivation of atmospheric aerosol extinction profile.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738227 (2009) https://doi.org/10.1117/12.831320
This non-invasive gas monitor for exhaust gas monitoring must has high reliability and
requires little maintenance. Monitor for in-situ measurements using tunable diode laser absorption
spectroscopy (TDLAS) in the near infrared, can meet these requirements. TDLAS has evolved over the
past decade from a laboratory especially to an accepted, robust and reliable technology for trace gas
sensing. With the features of tunability and narrow linewidth of the distributed feedback (DFB) diode
laser and by precisely tuning the laser output wavelength to a single isolated absorption line of the gas,
TDLAS technique can be utilized to measure gas concentration with high sensitivity. Typical
applications for monitoring of H2S, NH3, HC1 and HF are described here together by wavelength
modulation spectroscopy with second-harmonic(WMS-2F) detection. This paper will illustrate the
problems related to on-line applications, in particular, the overfall effects, automatic light intensity
correction, temperature correction, which impacted on absorption coefficient and give details of how
effect of automatic correction is necessary. The system mainly includes optics and electronics, optical
system mainly composed of fiber, fiber coupler and beam expander, the electron part has been placed in
safe analysis room not together with the optical part. Laser merely passes through one-meter-long pipes
by the fiber coupling technology, so the system itself has anti-explosion. The results of the system are
also presented in the end, the system's response time is only 0.5s, and can be achieved below
1×10−5 the detection limit at the volume fraction, it can entirely replace the traditional methods of
detection exhaust gas in the process industry.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738228 (2009) https://doi.org/10.1117/12.833427
Offset frequency locking is widely applied in laser detection, frequency stabilization of lasers, laser accurate
measurement and laser spectroscopy. In the paper, an offset frequency locking system based on Field Programmable
Gate Array (FPGA) is designed and applied for cavity-dumped CO2 waveguide laser with two channels and common
electrodes. A scheme for all-digital frequency discriminator in the system is described in the paper. The frequency
discriminating precision of single pulse is improved by designing a high speed counter which could count both the rising
edges and falling edges of signals. The multi-pulse discrimination and the high probability mean filtering algorithm are
used to further improve the discriminating precision. At the same time, the algorithm of variable step length and
segmental approximation is used to improve the speed and precision of frequency modulation. The experimental results
show that with the method of multi-pulse discrimination the beat frequency is stabilized within ±10MHz.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738229 (2009) https://doi.org/10.1117/12.834907
Coherent optical detection technique has been widely used in communication and non-communication fields due to its
advantages in handling kinds of modulation formats and offering improved sensitivity and signal to noise ratio. We
present an acousto-optic signal processing system using coherent detection technique. Firstly the principles of Bragg
diffraction and coherent optical detection are introduced. And then how to combine coherent detection with
acousto-optic deflection to achieve signal processing is discussed. As to improve the efficiency of the space coherent
optical detection, an approach that signal and reference beams are respectively injected into corresponding
polarization-maintaining (PM) fibers before combining is put forward. In this way, the fluctuation of the state of
polarization of the two beams is overcome. Through beam collimation, polarization-state control and Fourier transform
(compression processing), the acousto-optic deflector is ensured to get higher diffraction efficiency over the whole
frequency band of operation. Meanwhile, the impact that the surrounding environment has on the mixing of signal and
reference beams is decreased, and the level of complexity and difficulty in optical system alignment is also reduced. At
last, computer simulation has shown that the SNR is much depended on the linewidth of laser. When the coupling optical
aperture and laser energy injection efficiency are ensured to meet demands, experiments have proven that, by injecting
beam into PM fiber, the influence background light has on combining is weakened so that it is easier to keep polarization
matched between signal and reference beams, and thereby the efficiency of coherent optical detection can be greatly
improved.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822A (2009) https://doi.org/10.1117/12.836263
The improving resolving power of laser imaging system is limited by the laser footprint size on the target. Employing
only echo delay and intensity information, the information of the targets inside the footprint is difficult to be obtained for
the echo signal of the targets maybe is submerged by each other. Under the remote laser imaging, the serious loss of
image quality may occur because of the large footprint. The target detection method based on the single laser return
waveform was studied and the provided to get the target information inside the laser footprint. Firstly, the basis laser
echo signal model of the target inside the footprint was built. On the basis, the decomposition algorithm was provided
which can decompose a laser return waveform into a series of components assuming that each component corresponding
to a sub-target inside the laser footprint. After the primary sub-target return waveforms was obtained, however, there still
exists some small sub-targets inside the laser footprint whose return signal is hardly to be extracted because they are
submerged by the neighborhood sub-target return signal. The subtracting algorithm between the whole return waveform
and the components waveform provides the way to get the submerged return waveforms of sub-target. So, the
information of sub-targets inside the laser footprint would be obtained. In the end, the actual laser return data was
analyzed employing the method to get the range position information of the sub-targets inside the laser footprint, which
verifies the method validity.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822B (2009) https://doi.org/10.1117/12.833703
The laser relay mirror technique has been under extensive research in recent years. The concept and the working process
of the relay mirror system are analyzed in this paper. The model of the relay mirror system is established, the effect on
1km-altitude target with 500 m/s flying speed of the relay mirror system and the conventional ground-based laser system
are calculated respectively. Obtains that the maximum coverage range of the ground-based laser system is 2.0 km and the
maximum coverage range of the relay mirror system is 23.2 km. The relay mirror can largely open up the coverage range
of the laser system and strengthen the attacking ability of the ground-based laser.
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Zhiqiang Mi, Xiaoxuan Xu, Junmei Li, Bin Wang, Yufang Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822C (2009) https://doi.org/10.1117/12.836725
With the use of nano-structure metal film and the angle incident laser which has specific wavelength and
polarization, it will form surface plasma resonance, and we can see several orders of SERS phenomenon. This
phenomenon can be widely used in the area of military. Such as the detection of the mine, the investigation of the
concentration of toxic gas. This paper mainly describes a way of fabrication of the nano-structure metal film: at first
fabricate a honeycomb structures of aluminum oxide template, the second plate the alumina template with silver, at
last dissolve the alumina template with hydrochloric acid. Thus ordered silver nano arrays is formed. Experiment
prove it is a very well substrate for SERS.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822D (2009) https://doi.org/10.1117/12.835290
As a high resolution imaging sensor, synthetic aperture ladar data contain phase-error whose source include
uncompensated platform motion and atmospheric turbulence distortion errors. Two previously devised methods, rank
one phase-error estimation algorithm and iterative blind deconvolution are reexamined, of which a hybrid method that
can recover both the images and PSF's without any a priori information on the PSF is built to speed up the convergence
rate by the consideration in the choice of initialization. To be integrated into spotlight mode SAL imaging model
respectively, three methods all can effectively reduce the phase-error distortion. For each approach, signal to noise ratio,
root mean square error and CPU time are computed, from which we can see the convergence rate of the hybrid method
can be improved because a more efficient initialization set of blind deconvolution. Moreover, by making a further
discussion of the hybrid method, the weight distribution of ROPE and IBD is found to be an important factor that affects
the final result of the whole compensation process.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822E (2009) https://doi.org/10.1117/12.835576
The performance of passive photoelectric detection system for target detection is seriously affected by many factors,
such as the background light, the weather condition and the target temperature contrast, etc. To overcome the
disadvantages of the passive detection system, lots of domestic and foreign institutes are focusing on the research of the
laser active imaging detection system. Laser active imaging system based on range-gated technology use high peak
power laser pulse to illuminate the target, meanwhile use the receiving system with synchronization control circuit to
detect part of the reflected light from the target for imaging. It can efficiently suppress the brightness noise and the
backscattering noise, and apparently advance the imaging and identification performance for small dark target far away.
In this paper, on analyzing the principle of the range-gated laser active imaging technology, we studied the system range
performance limited by SNR thresholds due to the detector noise and the background noise respectively. By analyzing in
theory and simulation calculation, we made out the relationship between system range performance and other system
parameters in certain atmosphere conditions. The parameters include peak laser power, laser divergence angle, imaging
system resolution, target contrast, system SNR, etc.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822F (2009) https://doi.org/10.1117/12.833597
Laser coherent detection makes use of the coherence of laser to pick up weak laser signal by an optical LO (local
oscillator) signal. Compared to direct detection, coherent detection has higher sensitivity and could get the frequency
difference between incident signal and LO. Traditional coherent detection systems are composed of free space optical
components; the systems were complicated and hard to adjust. We built an all-fiber MOPA heterodyne laser detection
system by DFB laser, AO frequency Shifter, polarization beam splitters, polarization maintaining couplers and balanced
photo receivers. Because the coherence of laser beams is relative to the alignment of polarizations states, our system uses
double-balanced structure. The balanced detection structure greatly reduces the relative intensity noise of the LO. In the
article, the theory of coherent detection and the double balanced coherent detection are presented; the design of detection
electronic circuits is also discussed. The high coherent efficiency of fiber-optic detection system and high sensitivity of
coherent detection are proved by experiment. Some problems caused by fiber optics are also introduced.
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Yu-feng Peng, Juan Wang, Xiao-qun Bi, Ming-gao Zhang, Zu-hai Cheng
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822G (2009) https://doi.org/10.1117/12.835022
Based on the laser fields from a positive confocal unstable resonator (ab initio), the propagation characteristics of
the beam through turbulent atmosphere are investigated by means of fast Fourier transform algorithm (FFT). To
conveniently investigate the propagation characteristics of laser beam through the atmosphere, as far as known, in
the previous many works, a mathematical expression was generally artificially predefined to represent the given
laser beam, such as Gaussian beam, Hermite-cosh-Gaussian beam, flat topped beam, dark-hollow (annular) beam,
etc. In this paper, by basing on the initial built in oscillation of a laser resonator, such as a positive confocal unstable
resonator (CUR), we studied the intensity distributions of the output laser field to obtain the propagation
characteristics of laser beam through the turbulent atmosphere as functions of different propagation distances. The
results show that the turbulence will result in the degradation of the peak value of the laser intensity in the far field,
the spread of the far field diagram patterns, and the beam quality characteristics greatly degraded.
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M. N. Akram, V. Kartashov, K. Wang, G. Ouyang, X. Chen
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822H (2009) https://doi.org/10.1117/12.835459
Speckle is the constructive and destructive interference pattern observed from an optically
rough surface when a highly coherent laser light is used as the illumination source. In this article, we
present some methods to reduce the undesired laser speckle in laser display projector and show
measurement results indicating reduction in speckle contrast obtained by using a dynamical flexible
polymer-based diffraction grating phase modulator. Light is diffracted into multiple orders by the dynamic
polymer diffraction grating. This diffracted light, after collection and homogenization, is used as the
illumination source for displaying picture information. Due to the time-varying phase of the diffraction
grating, the diffraction pattern changes thus creating time-varying speckle patterns on the rough screen. The
time-varying speckle is captured by a CCD camera with appropriate integration time to mimic the
averaging action of the human eye. Thus the time-integrated speckle is minimized by the intensity
averaging of many independent speckle patterns. Different configurations of the diffraction grating along
with random phase plate and beam combining lens were explored to ascertain the corresponding reduction
in speckle contrast and its dependence on the time-period of the driving voltage of the diffraction grating.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822I (2009) https://doi.org/10.1117/12.837128
Simulation experiment of adaptive optics compensation to thermal blooming phase distortion induced
by high energy laser propagation in the atmosphere are carried out. The results of spot pattern and Strehl ratio in
the focal plane are obtained when the adaptive optics system is in the open or closed loop shape. The effect of
adaptive optics compensation is prominent when the Bradley-Hermann distortion number ND is less than 300,
and Strehl ratio is more than 0.4 on the whole. Phase compensation instability appears when the distortion
number ND becomes greater than 300, in this case, the compensated beam Strehl ratio goes down rapidly. The
experimental Strehl ratio without adaptive optics compensation agrees well with that of the thin lens
approximation theory, while the one with adaptive optics compensation has some deviation with that of the
ray-optics approximation theory.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822J (2009) https://doi.org/10.1117/12.835279
Gyroscope used as surveying sensor in the oil industry has been proposed as a good technique for measurement-whiledrilling
(MWD) to provide real-time monitoring of the position and the orientation of the bottom hole assembly
(BHA).However, drifts in the measurements provided by gyroscope might be prohibitive for the long-term utilization of
the sensor. Some usual methods such as zero velocity update procedure (ZUPT) introduced to limit these drifts seem to
be time-consuming and with limited effect.
This study explored an in-drilling dynamic -alignment (IDA) method for MWD which utilizes gyroscope. During a
directional drilling process, there are some minutes in the rotary drilling mode when the drill bit combined with drill pipe
are rotated about the spin axis in a certain speed. This speed can be measured and used to determine and limit some drifts
of the gyroscope which pay great effort to the deterioration in the long-term performance. A novel laser assembly is
designed on the wellhead to count the rotating cycles of the drill pipe. With this provided angular velocity of the drill
pipe, drifts of gyroscope measurements are translated into another form that can be easy tested and compensated. That
allows better and faster alignment and limited drifts during the navigation process both of which can reduce long-term
navigation errors, thus improving the overall accuracy in INS-based MWD system. This article concretely explores the
novel device on the wellhead designed to test the rotation of the drill pipe. It is based on laser testing which is simple and
not expensive by adding a laser emitter to the existing drilling equipment. Theoretical simulations and analytical
approximations exploring the IDA idea have shown improvement in the accuracy of overall navigation and reduction in
the time required to achieve convergence. Gyroscope accuracy along the axis is mainly improved. It is suggested to use
the IDA idea in the rotary mode for alignment. Several other practical aspects of implementing this approach are
evaluated and compared.
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Zhi-chao Wu, Guang-yong Jin, Xue-chun Tan, Ming Ling, Zhu Liang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822K (2009) https://doi.org/10.1117/12.835703
Laser blood-sampling device is one of the foremost tasks in medicine domain. It has a lot of merits such as un-touching,
avoiding infection, indolence, and fast healing etc. The Er:YAG laser with wavelength of 2.94μm which is just close to
the absorbency peak of water can be strongly absorbed by water molecular, so it has very wide application value in
clinical medicine. In the paper, based on the mutual action characters of the laser with 2.94μm wave length on biological
tissues, such as high absorption, acting on surface, the design of a new type of laser blood-sampling device is introduced.
According to the needs of practice, the main component of the blood-sampling device is the laser, which includes optical
resonator, optical collector, pumping source, optical guidance and focusing system. All of them are designed in the
paper, and the reflection index of output coupling mirror of laser is optimized, the laser threshold is reduced, and
pumping efficiency is improved. Moreover, thermal effect of Er:YAG solid-state laser is analyzed and a reasonable
cooling method is designed. As a result, an excellent laser blood- sampling is obtained, the maximum output power is
about 1J, the optical to optical conversion efficiency is 1.2%. For the better production-grade, the cuprum-based
conduction is adopt to eliminate heat, the precision modulation and fixing of the optical resonance is achieved by the
special adjusting structure that not only improve the stability and reliability, but also reduce the size of laser bloodsampling
device. The size is 110×190×320mm, the weight is about 5.8kg, and the laser blood- sampling efficiency is
100%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822L (2009) https://doi.org/10.1117/12.835496
Based on the method of measuring turbulence profile with lidar, equations of backscattering speckle sizes induced by
aerosol and turbulence are given. According to the relationship between diaphragm aperture and sizes of speckles,
fluctuations of normalized variance of echo signal can be separated into dilution regime of aerosol and turbulence,
turbulent regime and smoothed regime. The feasibility of measuring turbulent profile with MPL-A1 lidar is discussed,
and experiments are performed in horizontal direction. According to the values of SNR and values of normalized
variance of echo signal, effective measuring distances of this lidar are determined. The variations of normalized variance
and those of calculated results of scintillation index, which are both depending on propagation distance, are compared.
Results show that, although the values of normalized variance are only 10 percent of the latter, there is much
comparability, especially during nighttime. Temporal variations of normalized variance, which are calculated at 1950m
during daytime and at 4500m during nighttime, are compared with those of refractive index structural constant. Analyses
show that, the fluctuant ranges of them are all about one magnitude. Although there are a small quantity of time
differences between them, total tendencies are comparable.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822M (2009) https://doi.org/10.1117/12.834809
Laser underwater target image acquired by using synchronization-scanning imaging technology is always disturbed by
strong laser beam. Correlation analysis algorithm based on texture-driven cannot detect target in these images at first
hand. In these laser images energy of mighty laser beam is converged in a certain direction, on the contrary distribution
of weak target energy is symmetrical in all directions. Some certain multi-scale and multi-channel Gabor filters can boost
up some certain direction energy and at the same time decrease other certain direction energy. Therefore, the mighty
laser beam with single certain direction in the image is restrained by appropriate Gabor filters. In order to gain the better
result, firstly small size Gabor filters with four directions are used to process the laser target image, then scale size of
Gabor filter is increased step by step until result image processed by Gabor filters is approving. After that texture-driven
correlation analysis algorithm is processed on the image filtered by Gabor filters with appropriate size and direction and
then weak target is detected. Experiments prove that the proposed algorithm based on Gabor filter can efficiently
eliminate interference of mighty laser beam and detect laser underwater image target effectively.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822N (2009) https://doi.org/10.1117/12.835651
Optical ranging is one of the most precise techniques for distance measurement. The effects of the
density variation of atmosphere, aerosols and clouds on optical ranging precision are generally
considered, a new method is proposed for calculating the ranging precision in the presence of aerosol
particles and clouds. The size distribution spectrum models for aerosols and clouds in the Optical
Properties of Aerosols and Clouds Package (OPAC) are adopted. Results show that aerosols and clouds
could introduce errors of several centimeters to several ten meters to the ranging. The relationship
between the ranging precision and the relative humidity, the zenith angle of ranging direction and the
optical wavelength is also analyzed. The ranging error doesn't have an obvious relationship with the
wavelength, but depends on the zenith angle, especially for the angle larger than 70 degree. The
ranging error depends on the relative humidity as well. The ranging error induced by aerosols increases
gradually with the increase of the relative humidity when the relative humidity is less than 80%, but it
increases rapidly when the relative humidity is larger than 80%. Our results could provide a theoretical
basis and reference for the application of optical ranging.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822O (2009) https://doi.org/10.1117/12.834966
The detection and recognition performance of photoelectric detector for occluded target is very important in complicated
battlefield environment. It is one of the key factors to win a battle. Three key techniques of imaging lidar for occluded
target recognition are investigated, including the range-gated scannerless imaging, determination of range gate, spectrum
and polarization imaging. The range gate is determined by using modulated gain, pulse width measurement and inference
distinguishing of ground object echo and movement flatform. The project of an imaging lidar for occluded target
recognition is designed through the combination of hardware and software algorithm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822P (2009) https://doi.org/10.1117/12.835716
The results of an experimental and theoretical study of the proprerties of a LD pumped laser using a plano-concave
stable resonator are presented. The influence of thermal lens effect on laser output mode and beam quality has been
discussed briefly by using the transfer matrix theory. In this paper, further experiment on the output beam quality of a
LD pumped acousto-optic Q-switched laser has been also performed by adopting Hartmann-Shack wavefront sensor and
Zernike mode reconstruction theory. Using this method, the PV and RMS values of the aberration wavefront, the frontal
35-order Zernike aberrations can be acquired, and the Strehl ratio curve of the output beam and the distribution of circle
energy can also be obtained by calculation, so the mode properities can be fully understood. The experimental results
show that the beam wavefront aberration is mainly concentrated in the frontal 15 orders of Zernike aberration, mainly
including the defocus A3, the low-order astigmatism A4 and A5, and the coma aberration A6 and A7 because of the crystal
thermal effect.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822Q (2009) https://doi.org/10.1117/12.834697
Faced with different parameters in nowadays commercial airborne LiDAR market, a common evaluation standard based
on the user requirements including data quality and efficiency was developed to help users select a proper device. In this
paper, user requirements and data evaluating method were firstly discussed to build up a link between accuracy and
acquired footprints. Then, the relations between the coordinates of footprints and parameters were thoroughly analyzed.
The parameters were classified into basic and derived parameters, and a common evaluation standard was set up to
uniform these parameters according to data quality and efficiency. Furthermore, to demonstrate the effectiveness of the
standard, different parameter configurations were presented according to three different scenarios. The common
evaluation standard will help users to clarify and uniform the understanding of parameters.
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Zhong Ren, Guodong Liu, Zhen Huang, Wenping Zeng, Dongmei Li
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822R (2009) https://doi.org/10.1117/12.835004
In this paper, the photoacoustic spectroscopy (PAS), a novel, hybrid, noninvasive imaging modality, is used to monitor
the change of glucose concentration. A laser light with wavelength of 532nm is irradiated into the sample, The PA signal
is detected by the ultrasonic transducer based on the thermal-expansion effect, which can reflect the biochemical
properties of the biological tissues e.g., blood. Although PAS has better resolution and deeper penetration than others, the
PA signal is unavoidably polluted by some noises. In order to remove these noises to improve the precision and the
signal-to-noise ratio(SNR) of the glucose concentration, an improved wavelet threshold function is proposed. Meanwhile,
to eliminate the Pseudo-Gibbs phenomenon, the improved threshold function combines translation-invariant(TI)
algorithm to further improve the denoising effect. This threshold function can be looked as the compromise between
Donoho's soft-threshold function and hard-threshold function. Experimental results show that the denoising result of
improved function is better than that of Donoho's threshold functions and the semisoft-threshold function proposed by
Gao, etc. The improved function with combined TI algorithm denoise not only gets higher SNR and lower
root-mean-square error(RMSE), but makes the PA glucose spectral smoother. The SNR increases from 27.3658 to
44.7060, the RMSE decreases from 0.272 to 0.017.
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Nicolas Rivière, Laurent Hespel, Marie-Thérèse Velluet, Yves-Michel Frédéric, Philippe Barillot, Franck Hélias
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822S (2009) https://doi.org/10.1117/12.836829
Onera, The French Aerospace Lab, has developed a new active burst illumination imaging system with a short time
gating. This imaging device is used to obtain a passive or an active image of a small volume of the illuminated scene. To
better understand and evaluate the relevant physical phenomena (scintillation, speckle...) impacting on the performance
on burst illumination imaging system, Onera has implemented a code (PIAF). The aim of this paper is to describe the
model and to present some first results. Efforts have done on three principal points, the laser source model, the
propagation through the turbulence concerning the illumination of the scene, and the interaction with the target.
The model can take into account any laser sources. To evaluate the propagation through the atmosphere, electromagnetic
models are implemented but we specially focused our attention on simplified methods to reduce computing time.
Considering the 3D target and its elementary plane surfaces, we analyze each contribution like the incoherent solar field
or the incident laser field. We adapt classical and physical models for light reflection. Speckle contributions are also
treated using data bases generated by an Onera tool. In the last section of this paper, we attempt to model artefacts
associated with such imaging devices, including photon noise, gain issues and electronic noise. We also present
experimental results and comparisons with Piaf simulations in an associated paper.
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L. Hespel, M. T. Velluet, A. Bonnefois, N. Rivière, M. Fraces, D. Hamoir, B. Tanguy, B. Duchenne, J. Isbert
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822T (2009) https://doi.org/10.1117/12.836753
Laser Gated Imaging is a unique camera technology. It provides long-range night vision in complete darkness as well as
in degraded weather conditions, such as rain, fog and haze. Burst illumination laser (BIL) imaging combines an active
laser illumination with time gating (or range gating) camera. For these reasons, BIL imaging has become increasingly
important in Defense and security applications. In an associated paper [01], we present a model (PIAF) developed to
evaluate the relevant physical phenomena (scintillation, speckle...) impacting on the BIL imaging. This paper presents
preliminary experimental results and comparisons with PIAF simulations.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822U (2009) https://doi.org/10.1117/12.836723
The primary characteristics of light scattering by water medium and small particles are analyzed based on the
scattering theory. Compare the differences between two method to fix the deflection angle, one is Rayleigh expressions,
the other is sampling the H-G function. The light scattering intensity distribution on conditions of variety of wavelengths
and particle's semidiameters are calculated using Mie scattering expressions. The emluator of photon moving underwater
is completed, which is validated taking exponential attenuation law of beam transmitting as standard, then several set of
simulations proceed, accordingly some rules of underwater optical echo signal are concluded. In the end, the attenuation
experiment of beams in different wavelengths, and the experiment of pulse laser detecting underwater air bubble film are
conducted.
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Yong Zhang, Yuan Zhao, Liping Liu, Jiang He, Xiudong Sun
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822V (2009) https://doi.org/10.1117/12.835800
Gain modulation ladar is a cutting-edge ladar system. To eliminate the image distortion caused by target movement, two
ICCDs are adopted to detect simultaneously and get the range image of object. This article presents a research on the
working mechanism and range resolution of non-scan ladar based on gain modulation. The research suggests that
ICCD's relatively low SNR is one of the bottlenecks of further improvement of system performance. To address this
issue, an improved system was designed and studied with regard to its range resolution. Experimental results indicated
that the proposed system was superior to the ladar system adopting double ICCDs in the aspects of range resolution, etc.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822W (2009) https://doi.org/10.1117/12.835863
The reconnaissance satellite, communication satellite and navigation satellite used in
the military applications have played more and more important role in the advanced technique
wars and already become the significant support and aid system for military actions. With the
development of all kinds of satellites, anti-satellite laser weapons emerge as the times require. The
experiments and analyses of laser disturbing CCD (charge coupled detector) in near ground have
been studied by many research groups, but their results are not suitable to the case that using laser
disturbs the satellite-based detector. Because the distance between the satellite-based detector and
the ground is very large, it is difficult to damage it directly. However the optical receive system of
satellite detector has large optical gain, so laser disturbing satellite detector is possible. In order to
determine its feasibility, the theoretical analyses and experimental study are carried out in the
paper. Firstly, the influence factors of laser disturbing satellite detector are analyzed in detail,
which including laser power density on the surface of the detector after long distance transmission,
and laser power density threshold for disturbing etc. These factors are not only induced by the
satellite orbit, but dependence on the following parameters: laser average power in the ground,
laser beam quality, tracing and aiming precision and atmospheric transmission. A calculation
model is developed by considering all factors which then the power density entering into the
detector can be calculated. Secondly, the laser disturbing experiment is performed by using LD
(laser diode) with the wavelength 808 nm disturbing CCD 5 kilometer away, which the disturbing
threshold value is obtained as 3.55×10-4mW/cm2 that coincides with other researcher's results.
Finally, using the theoretical model, the energy density of laser on the photosensitive surface of
MSTI-3 satellite detector is estimated as about 100mW/cm2, which is largely exceed the
disturbing threshold and therefore verify the feasibility of using this kind of laser disturbing the
satellite-based detector. According to the results. using the similar laser power density absolutely
saturate the requirements to laser disturbing satellite-based detector. If considering the peak power
of pulsed laser, even decrease laser average power, it is also possible to damage the detector. This
result will provide the reliable evidences to evaluate the effect of laser disturbing satellite-based
detector.
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Liping Su, Weijiang Zhao, Deming Ren, Yanchen Qu, Xiaoyong Hu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822X (2009) https://doi.org/10.1117/12.834911
For the detection of the bubble-laser-scattering property, it is the key to improve the signal to noise ratio. The various
noises in the bubble-laser-scattering signal, the background light, power frequency of 50Hz, radio frequency noise and
inherent noise within the electronic system, are analyzed in detailed. Two frequency-domain methods used to process the
bubble scattering signal, the Fourier transform and the power spectral estimation, are focused on. These two methods can
reduce the noise, isolate the DC component and eliminate the impact of the power frequency of 50Hz, thus the pulse of
bubble laser scattering could be detected. The physical meaning for the power spectral estimation is much clearer than
that of the Fourier transform. The power spectrum curve obtained by using the Yule-Walker AR (regression model)
method is much smoother and its frequency resolution is higher than the other methods. The results show that the Yule-
Walker AR spectrum estimation is the most reasonable and most effective method.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822Y (2009) https://doi.org/10.1117/12.835512
A high efficient ring-cavity optical parametric oscillator at 1.57μm eye-safe range using three non-critically phasematched
KTP crystals is researched and experimentally demonstrated. The primary advantage of the ring-cavity OPO is
that the resonator mirrors are at 30 degrees to the pump beam, so they do not provide any feedback to the pump laser.
The signal energy of 75mJ with the pulse width of 6.6ns is obtained under the input pump pulse of 200mJ. This result
provided a clear demonstration that high pump-to-signal energy conversion (up to 37.5%) can be achieved from the ringcavity
OPO by single-pass pumped method.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73822Z (2009) https://doi.org/10.1117/12.834944
A novel distributed feedback fiber laser accelerometer based on silicon rubber is developed. The unique mechanism
employed for the accelerometer ensures uniform strain distribution on the fiber laser's Bragg element. A mathematical
model of single-degree-of-freedom system is established, giving the expression of the sensitivity and resonant frequency
of the accelerometer. A multiple-degree-of-freedom simulation with finite element method is also conducted, giving a
more precise prediction of accelerometer's characteristic. Several accelerometers of this type are constructed and tested.
The wavelength shift signal is demodulated using phase generated carrier technique. The experimental result shows they
have a sensitivity of 72 pm/G and a resonant frequency of 415Hz, which agree well with the simulation results. The
minimum detectable signal of the whole sensing system is about 1.5μg. The accelerometer's structure is simple and the
components employed are all commercially available, indicating a great potential in practical use.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738230 (2009) https://doi.org/10.1117/12.835662
The FM/cw lidar has the advantages of narrow receive bandwidth, non-range-ambiguity, enhanced ability of
anti-jamming etc. A summary of FM ranging theory is introduced. The FM/cw lidar system is designed with the
incoherent detection approach, which contained the transmitter, receiver and signal processing system, the system
complexity and realization difficulty are reduced significantly. The transmitter is consisted of chirp signal generate
module, laser modulate system and laser transmit subsystem. Receiver is consisted of receive optical system, photo
electricity detector, amplifier and mixing. Signal process system is consisted of lowpass, IF amplifier, signal
collecting and processing system. The main affect factors are analyzed, the modulate depth and mixing efficiency
effect to the detection capability are simulated, which are the special to the FM/cw lidar based on the designed
FM/cw lidar system. The simulation results indicate that the detection capability can be improved efficiently by
enhance the modulate depth and mixing efficiency. The research results establish the theory and realization basic to
the research on the FM/cw lidar.
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Youqiang Liu, Yinhua Cao, Chunxiao Xu, Wenbin Qin, Zhiyong Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738231 (2009) https://doi.org/10.1117/12.835709
KW-class high-beam quality diode laser system was introduced in this paper. In this system, the wavelengths of 808nm,
915nm, 940nm, and 980nm were used for the wavelength coupling and polarization coupling. The wavelength coupling
and polarization coupling can reach the optical efficiency of 91.4%. Before wavelength coupling, polarization coupling
and beam shaping, the maximum output power of the laser was 1200W, and after that, 1031W was achieved, so the
overall conversion efficiency reached 85.9 %. 12mm • mrad of the output beam quality was realized in both the fast axis
and the slow axis. Through intelligent control, the diode laser can work in different wavelength, different power and
different pulse width. Because of its output power and beam quality, this laser system can be used in the
ultra-long-distance laser detection, laser remote sensing and many other demands.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738232 (2009) https://doi.org/10.1117/12.836539
This paper mainly reports long term laser frequency stabilization combined Pound-Drever-Hall technique with Dopplerfree
saturated spectroscopy technique for application in sodium resonance fluorescence Doppler lidar. A single-mode
dye laser with Pound-Drever-Hall frequency stabilization is employed in this lidar system. But the center frequency of
the laser can drift due to temperature changes or piezo actuator relaxation. To reduce these drifts, a sodium Doppler-free
saturated fluorescence spectroscopy system is set up and the sodium Doppler-free features are used as absolute frequency
references to lock the laser frequency. A sodium vapor cell is heated to and stabilized at 65ºC in order to provide
sufficient atomic sodium vapor density. A photodiode is placed adjacent to the sodium vapor cell to detect the laserinduced
fluorescence. The frequency stabilization operation is based on LabVIEW program.In reaction to the error signal,
this software program will act via the dye laser controller on the reference cell piezo actuator to keep the master
resonator on the sodium fluorescence spectrum line. In this lidar system, we lock the laser frequency at sodium D2a line
with ~4MHz precision for hours.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738233 (2009) https://doi.org/10.1117/12.835501
Parametric edge detector has been reported to be successfully applied in actual coherent ladar intensity images corrupted
by speckle. Parametric edge detector derived from an exponential model for the speckle which has been described as a
multiplicative noise corrupting intensity images. The performance of the noises is not the same when the intensity
images are gained in different distance. So the application scope of this algorithm is of great value in actual ladar. In the
paper, parametric edge detector, morphological filter based on parametric edge detector and Canny detector are used to
detect coherent ladar simulated intensity images. The edge detection results are obtained and compared, when the values
of carrier-noise-ratio (CNR) are changed. From the simulation results, the best application scope of parametric edge
detection is described.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738234 (2009) https://doi.org/10.1117/12.835970
In coherent imaging ladar system, the round-trip time and the scan rate cause the deviation between the received signal
and the transmitter beam in spatial directionality. Therefore the return signal angle lags behind the receiving optical axis
angle. This lag-angle effect will cause energy loss and even the loss of return signals, which would finally affects the
image quality. In order to overcome the impact of lag-angle effect on image quality, the detector with rectangular active
area has been presented to replace the circular detector. In this paper, the numerical simulation of heterodyne efficiency
based on rectangular detector is analyzed. And the simulation results show that heterodyne efficiency quickly declines
with offset of return signal along optical axis when lag-angle effect exists. When the offset is below 0.5 and the
length-width-ratio is around 1.5, the heterodyne efficiency is above 50%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738235 (2009) https://doi.org/10.1117/12.834579
We experimentally measured the spectral and the temporal properties of various emissions from the Rhdamine 6G dye
solution pumped by picosecond laser pulses. These emissions involve the transverse amplified spontaneous emission
(ASE), the longitudinal ASE, the longitudinal ASE coupled with partial and stronger coherent feedback, and the random
laser. The random laser is made by adding TiO2 nanopowder to the dye solution as scatterer. The spectral and the
temporal shapes and widths of these emissions are measured using a spectrometer and a streak camera combined with a
CCD. The transverse ASE and the longitudinal ASE have similar spectral widths, while the longitudinal ASEs coupled
with the coherent feedback show narrowed spectral widths. The pulse shapes and widths of the longitudinal ASE with
coherent feedback show how the coherent feedback comes to existence. The experimental results show clearly the effect
of the degree of the coherent feedback on the spectral narrowing. The spectra and the pulses of the random laser of some
scatterer densities are presented, showing that the random laser without sharp peaks also has partial coherent feedback in
it at certain scatterer densities in the weak scattering regime.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738236 (2009) https://doi.org/10.1117/12.835678
A mass of reactive oxygen species(ROS) are produced in the process of smoking. Superfluous ROS can induce the
oxidative stress in organism, which will cause irreversible damage to cells. Fluorescent probe is taken as a marker of
oxidative stress in biology and has been applied to ROS detection in the field of biology and chemistry for high
sensitivity, high simplicity of data collection and high resolution. As one type of fluorescent probe, dihydrorhodamine
6G (dR6G) will be oxidized to the fluorescent rhodamine 6G, which could be used to detect ROS in mainstream
cigarette smoke. We investigated the action mechanism of ROS on dR6G, built up the standard curve of R6G
fluorescence intensity with its content, achieved the variation pattern of R6G fluorescence intensity with ROS content in
mainstream cigarette smoke and detected the contents of ROS from the 4 types of cigarettes purchased in market. The
result shows that the amount of ROS has close relationship with the types of tobacco and cigarette production
technology. Compared with other detecting methods such as electronic spin resonance(ESR), chromatography and mass
spectrometry, this detection method by the fluorescent probe has higher efficiency and sensitivity and will have wide
applications in the ROS detection field.
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You-wei Huang, Wei-qi Jin, Kun Ding, Hai-lan Li, Feng-mei Cao, Xia Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738237 (2009) https://doi.org/10.1117/12.836672
The imaging of underwater objects which have been illuminated by natural or artificial light has been of long-standing
interest to investigators working in oceanographic environments. Analysis of the propagation of imaging light through
water is complicated by extreme attenuating and scattering properties of water, especially multiple scattering. A
comprehensive computer model to simulate the formation of underwater images has been presented in this article. The
model incorporates the temporal and spatial broadening properties of the propagation of light in water. A degraded image
is approximated as a convolution of an initial image and point spread functions (PSFs). The spatial PSF plays a
significant role in describing the spatial propagation of light and image blurring due to forward scattering. The temporal
PSF can describe the pulse broadening effect, which is of great significance to evaluate the performance of range-gated
technology. Computed and measured images compare favorably. It is concluded that the use of spatial and temporal
broadening models are convenient and viable techniques for analytic computation of underwater images.
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Da Xu, Jian-xun Zhao, Jun-biao Hu, Hua Li, Chuan-you Wang, Bing-wei Li
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738238 (2009) https://doi.org/10.1117/12.831398
The dynamical simulation model of the exposure device of laser detector is built up in ADAMS software. Aiming at
optimizing the movement law of the pole and minimizing the maximal value of load of key parts, the influences of the
spring stiffness coefficient,the damping coefficient, preload of spring and the mass of pole on the optimal goal are
discussed. The virtual prototype of the exposure device of laser detector has been optimized and the optimized
parameters are obtained. In order to choose the electromotor and material, intensity of key parts is checked based on
ANSYS. And the problem of TQC is solved effectively by this way.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738239 (2009) https://doi.org/10.1117/12.830689
The orientation of the dipole moment, which is one of important parameters in single-molecule fluorescence
spectroscopy, is determined by highly focused generalized cylindrical vector beams combined with a confocal far-field
microscope. A generalized cylindrical vector beam can be decomposed into a linear superposition of radially polarized
and azimuthally polarized components and the ratio of the radial and longitudinal components of the focal electric field
can be adjusted by changing the polarization direction. As compared to the case of a radially polarized incident beam,
numerical results demonstrate that fluorescence intensity difference among single molecules with different orientations
can be effectively overcome for a particular polarization direction of the generalized cylindrical vector beam, which may
increases the signal-to-noise ratio of the practical experiments and then ease the difficulty in orientation determination of
single molecules.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823A (2009) https://doi.org/10.1117/12.834954
Among novel optical design methods axial gradient index (AGRIN) gradually evokes attention accompanying by
manufacture technical maturity. In many papers AGRIN lens is equivalent to an aspheric plano-convex doublet whose
curvatures and radii are AGRIN vertexes's and plane surfaces are face to face. Nevertheless the aberrations after the
treatment are very drastically changing. To finding accurate equivalent relations is necessary. In our work geometric ray
track and numerical calculation are done and the accurate relations of AGRIN surface to aspheric surface are achieved.
At last an AGRIN singlet for rotating image is demonstrated to verify the validity of our results. A simulation is carried
out through optical design software and little aberrated variety is found. After merit treatment obtained aspheric
coefficients approach calculated values.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823B (2009) https://doi.org/10.1117/12.831412
Propagation properties of partially coherent dark hollow beams with rectangular symmetry through aligned paraxial
optical systems are investigated in this paper. Based on the unified theory of coherence and polarization, the analytical
formulae for cross-spectral density both in source and reference plane are derived in tensor forms with the help of
generalized paraxial Collins formula. By using the transmitting matrix law, we set up a general aligned ABCD optical
system in order to analyze the propagation properties of beams passing through it. Numerical results show that intensity
distribution in transversal output plane is easily influenced by coherence length in the source plane; oppositely it shows
no variation by varying beam orders or dark-size adjusting parameter. We also investigate varying effects of two sorts of
beam source parameters on degree of coherence in the transversal reference plane. Finally we show the relationship
between dark-size adjusting parameter and paraxial transmitting intensity. Results show that when we decrease dark-size
parameter to a certain number, the average intensity around the focal point disappear which is very different from
ordinarily situation. All results in this paper may provide an effect way to describe and treat atom trapping and guiding
by applying rectangular DHB.
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Xianzeng Zhang, Xiaoyan Wang, Zhenlin Zhang, Qing Ye, Shusen Xie
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823C (2009) https://doi.org/10.1117/12.831257
To evaluate the feasibility of middle ear bone ablation in-vivo with pulse CO2 laser. Healthy male New Zealand rabbits
were used in the experiment. Middle ear mastoid bone of animal model was completely exposed by surgeon with
conventional method, and then Pulse CO2 laser with a wavelength of 10.6μm and pulse lengths of about 10ms was used
to carry out the opening surgery. Laser fluence was 8.3 J/cm2 with a repetition rates of 60 Hz, the beam diameter was 1.0
mm. After opening surgery, whole middle ear mastoid bone was obtained and processed with traditional histological
method, the morphology changes and thermal damage around the opening window were examined by light microscope.
Total operation time and light irradiation time were recorded. It showed that pulse CO2 laser is suitable for the
fenestration operation in middle ear bone, and this no-touch technique not only can obtain the similar outcome as
traditional methods, but also present a lot of advantages compared to the traditional methods. With the development of
laser technology and the appearance of relative instruments, especially when the thermal damage was efficiently
controlled, fenestration operation in ear with laser systems will be possible in near future.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823D (2009) https://doi.org/10.1117/12.830928
To solve the laser weak echo detection under the clutter background, a dynamic programming (DP) technique
has been developed for the detection of weak targets. The primary advantages of DP are its sensitivity to weak
targets along with its robustness to laser echo glitter. DP technology turn searching track of the target into the
subsection optimization of the target. First, DP algorithm finds all track subsection of target. Second, these track
subsections are synthesized into the potential track of target. Third, the track of the same target is combined. Then
the detection outcome is found. Theory analysis and the simulated results indicate a sensitivity improvement of
detection performance over conventional detection algorithm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823E (2009) https://doi.org/10.1117/12.834303
A novel method of measuring flight trajectory for projectile was proposed. Seven light screen target (LST) was made up
of two laser sources, two optical detectors and five pieces of mirror, which can measure the flight parameters including
trajectory, direction and component velocity of three directions. The double Z-shaped LST was formed by laser light
which was reflected by four pieces of parallel mirror, while the V-shaped LST was formed by laser light which was
reflected by one piece of mirror. The cross points can be obtained by measuring the time when the projectile passing
through every light screen. A principle experiment was done on a smooth plane table using a laser pen, four pieces of
mirror and photodiode circuit by launching a steel ball. Velocity and position compare experiments were done
simultaneously. The relative difference of velocity measurement was less than 0.2%. The difference of position
measurement was less than 2mm. The results of velocity and position compare examination indicated the method
proposed in this paper is feasible.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823F (2009) https://doi.org/10.1117/12.835527
The complexity of the optical properties of atmosphere demonstrated in spatial and temporal characteristics causing
the effect of optical properties on laser engineering could not be determined simply. It is necessary to reproduce the
panorama of optical properties of atmosphere, and in this case the effect of optical properties on laser engineering could
be evaluated. The survey of optical properties of atmosphere is continuous; facing zillions of data that changed
instantaneously, the statistical method must be used while the original characteristic of optical properties of atmosphere
in spatial and temporal distribution should be restored. Measurements of laser beam propagation in the atmosphere are
taken. the wavelength is 0.946 μm and the transmission length is 2 kilometers. The data we achieved were made an
hourly average, and then the same parameter based on each hour were made a monthly average, in this sense each
parameter has 288 groups of data; the annual statistical characteristic value of different optical properties including
atmospheric temperature, humidity, wind speed, visibility and the refractive-index structure parameter C2Nwere
obtained. The molecular absorption, the aerosol particle scattering and extinction, the turbulence effects and the
comprehensive effect of light propagation in the atmosphere were analyzed and evaluated for the atmospheric conditions
in the whole year by using this method. The distribution and statistical characteristics of effects of atmosphere optical
properties on the propagation were carried out. Analysis results show that, thorough understanding of the atmospheric
optical properties in the application areas is very important to all kinds of laser engineering, including feasibility analysis
of laser engineering, optical system design and performance evaluation. And statistical analysis method is an effective
means to master the characteristics of complex system. It turns out that the effects of optical properties of atmosphere on
the laser engineering is complicated and various, and a statistical method for a study of the analysis of the complex
spatial and temporal distribution characteristics value is presented meanwhile.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823G (2009) https://doi.org/10.1117/12.835332
ADLINK PCI-9114 multifunction data acquisition card, signal amplifier and multiplexer board and power sensor are
used to establish the real-time measurement system of relative laser power. During producing laser, measuring and
showing thermoelectric and photoelectric signal, calculating parameter and drawing the curve of relative power. Parameters of laser output power and energy are concerned with researchers. These parameters are important for
evaluating laser system. In this paper, a real time laser power measure system is established. While laser system is
operating, real time laser power measure system measured the power and energy of laser and plotted the waveform of
relative laser power. The parameters such as pulse width, rise time, fall time, power integration, average power, peak
power and average energy are computed.
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Zhenmin Shen, Tian Lan, Yinchao Zhang, Guoqiang Ni
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823H (2009) https://doi.org/10.1117/12.836558
Signal to noise ratio (SNR) is a key parameter in laser radar system. In this paper, the principle and composition of a new
type of airborne three-dimensional gazing gating imaging laser radar system are given. The signal model and the noise
model have been established respectively according to the working process of the new type of laser radar. Then the SNR
model has been built. Based on the SNR model, some important factors which influence the SNR have been analyzed.
SNR can be improved by optimizing the system inherent parameters which include laser wavelength, laser pulse energy,
receiving telescope diameter, the efficiency of launching and receiving optical system, and quantum efficiency of
intensified charge-coupled device (ICCD). Moderately sacrificing system resolution and operating height can also
improve SNR. It is shown by calculation and analysis that the most primary noise is the image intensifier quantum noise
and other noises are negligible. Also SNR is almost unchanged with the increasing of the overall electron gain (G) in the
whole actual range. Last the simplified SNR model is given according to the actual system parameters.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823I (2009) https://doi.org/10.1117/12.835606
This paper is a review of progress of laser rangefinders with digital signal processing. Correlation selection can be used
with reduced signal-detection threshold for a determined distance. Time-of-flight method of measuring the range, by
using in the detector channel a reduced signal-detection threshold for fixing the time position, in combination with
correlation selection to distinguish the signal pulses on a background of an intense flux of noise spikes, are proposed for
the possibilities of improving the detection and accuracy characteristics of pulsed laser rangefinders.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823J (2009) https://doi.org/10.1117/12.836601
In order to understand how pressure, temperature and CH4 and CO2 molecules effect Raman spectrum of
liquid water better, some experimental investigations of Raman spectrum of water with gas (CH4, CO2 and mixture of
CH4 and CO2) dissolved are carried out at different temperature (up to 350°C) under high pressure (40MPa) and under
different pressure (up to 40MPa) at room temperature using high-temperature and high-pressure set-up (top temperature
is 350°C and top pressure is 40MPa). The band of the stretching vibration of water between 3000 and 3800 cm-1 has
been studied. The results show pressure has little influence on Raman spectrum of water for all samples in our pressure
variation range while temperature affects Raman spectrum of water significantly in the range room temperature to
350°C. Peak position, FWHM and the parameter R21 all vary sharply along temperature. As temperature is raised,
peak positions shift to high frequency, FWHM decrease significantly and the parameters R21 increase with increasing
temperature as EXP function in studied temperature range for all samples. All these variations have a relation with
hydrogen bond. In addition, CO2 or CH4 dissolved in water makes all parameters vary along temperature more
obviously and the CH4 molecule modifies the Raman spectrum of H2O much than the CO2 molecule.
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Qian-jin Tang, Jie Shao, Zhi-zong Wu, Jian-yong Chen
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823K (2009) https://doi.org/10.1117/12.836561
Two laser guns with 2.95 mrad and 4.80 mrad beam divergence are designed to verify the relation of the measurement
time, measurement distance, speed range, and beam divergence. The on-the-road test result shows that 4.80 mrad beam
divergence is better than 2.95 mrad when measuring vehicle speed within 60 to 150 km/h at a distance 80~150 m, which
indicates that appropriately enlarging the beam divergence can extend active area and increase measurement speed range.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823L (2009) https://doi.org/10.1117/12.835721
A method of digital holography for high-resolution microscopy at long working distance is proposed using a synthetic
aperture. A series of digital holograms covered different spatial frequency ranges of an object optical field are recorded
by using different tilted object illuminations. Subsequently, the intensity images are numerically reconstructed and
magnified respectively. Finally, a synthetic image with the resolution improved and speckle noise suppressed is obtained
by synthesizing these reconstructed images. The results show that the proposed method can be easily used to in-situ
microscope at a long working distance.
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Lvming Zeng, Guodong Liu, Xuanrong Ji, Zhong Ren, Zhen Huang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823M (2009) https://doi.org/10.1117/12.835260
As a new field of combined ultrasound/photoacoustic imaging in biomedical photonics research, we present and
demonstrate a high-speed laser photoacoustic imaging system combined with digital ultrasound imaging platform. In the
prototype system, a new B-mode digital ultrasonic imaging system is modified as the hardware platform with 384
vertical transducer elements. The centre resonance frequency of the piezoelectric transducer is 5.0 MHz with greater than
70% pulse-echo -6dB fractional bandwidth. The modular instrument of PCI-6541 is used as the hardware control centre
of the testing system, which features 32 high-speed channels to build low-skew and multi-channel system. The digital
photoacoustic data is transported into computer for subsequent reconstruction at 25 MHz clock frequency. Meantime, the
software system for controlling and analyzing is correspondingly explored with LabVIEW language on virtual
instrument platform. In the breast tissue experiment, the reconstructed image agrees well with the original sample, and
the spatial resolution of the system can reach 0.2 mm with multi-element synthetic aperture focusing technique.
Therefore, the system and method may have a significant value in improving early detecting level of cancer in the breast
and other organs.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823N (2009) https://doi.org/10.1117/12.832613
Objective: to investigate the role of associated factors in the effectiveness of laser treatment for prolapsed
lumber intervertebral disc.
Method: 302 prolapsed lumber intervertebral discs in 212 patients were treated with percutaneous laser disc
decompression (PLDD). Patients were followed up by 12month, the associated factors which affecting the
effectiveness of treatment, ie age, duration of illness were analyzed.
Results: Punctual Success rate was 100%. After 12 month's follow up, 86% successful outcomes were
obtained, in which 93% successful outcomes were obtained in patients less than 50 years old, 92%
successful outcomes was obtained in the patients whose duration of illness less than 1 year.
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Weiguo Kong, Siying Chen, Yinchao Zhang, Guoqiang Ni
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823O (2009) https://doi.org/10.1117/12.835511
Pure Rotational Raman Lidar is a recently developed method for atmospheric temperature detection. Since the
Raman-scattering-signals are very weak, the photon-counting method is employed, which could be achieved by using a
multiscaler. Time delays, which exist among the trigger channel and the two count channels of the multiscaler, will affect
the corresponding relationship between the detected signals and the actual altitudes where the signals are returned, so it
is necessary to make some compensation. However, it is difficult to measure the time delays with traditional instruments
such as oscillograph, for there is no access to the final internal trigger signal or count signals. In this paper, a measuring
system is established, with a Digital Delay/Pulse Generator as the chief component, which is not usually used as a
measuring instrument. The measurement precision could reach about 50ps. Meanwhile, the compensating method is also
provided to improve the positioning accuracy of the lidar system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823P (2009) https://doi.org/10.1117/12.834576
A 16 channel distributed feedback fiber laser sensor array is reported. The spacing of neighbor lasers is
100 GHz and 200 GHz in turn. Compared with grating sideband reflection, Rayleigh backscattering from
~24 m long passive fiber is more responsible for the instability, and it's found that increasing the reflection
of grating could reduce the sensitivity of DFB FL to Rayleigh backscattering.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823Q (2009) https://doi.org/10.1117/12.835002
Fiber laser gas sensors based on the intra-cavity absorption spectroscopy require the use of gas cells. We propose a
simple and reliable gas cell using graded-index fiber lens (GFL) based all-fiber collimator. Conventional gas cells
usually utilize direct fiber-to-fiber coupling without collimators or graded-index (GRIN) lens as collimators. Direct fiberto-
fiber gas cell has simple configuration, but it suffers from high coupling loss and stray light interference. Gas cells
applying fiber pigtailed GRIN lens are advantageous to achieve low coupling loss. However, fiber pigtailed GRIN lens
requires accurate and complicated alignment and glue packaging which could compromise long term reliability and
thermal stability. The proposed technique fabricates all-fiber collimators by simply splicing a short section of gradedindex
fiber to single mode fiber which is both compact and durable. With that collimator, the gas cell can be fabricated
very thin and are suitable for extreme environments with high temperature and vibration. In this paper, we have carried
out experiment and analysis to evaluate the proposed technique. The coupling efficiency is studied versus different GFL
gradient parameter profiles using ray matrix transformation of the complex beam parameter. Experiments are also done
to prove the practical feasibility of the collimator. The analysis indicates that gas cell using GFLs can overcome the
disadvantages of traditional design; it may replace the conventional gas cells in practical applications.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823R (2009) https://doi.org/10.1117/12.830947
This paper presents a new pose measurement method of microminiature parts that is capable of transforming one
dimension (1D) contour size obtained by optical micrometer to three dimension (3D) data with six parameters for
microassembly. Pose measurement is one of the most important processes for microminiature parts' alignment and
insertion in microassembly. During the past few years, researchers have developed their microassembly systems focusing
on visual identification to obtain two or three dimension data with no more than three parameters. Scanning electronic
microscope (SEM), optical microscope, and stereomicroscope are applied in their systems. However, as structures of
microminiature parts become increasingly complex, six parameters to represent their position and orientation are
specifically needed. Firstly, The pose measurement model is established based on the introduction of measuring objects
and measuring principle of optical micrometer. The measuring objects are microminiature parts with complex 3D
structure. Two groups of two dimension (2D) data are gathered at two different measurement positions. Then part pose
with 6 parameters is calculated, including 3 position parameters of feature point of the part and 3 orientation parameters
of the part axis. Secondly, pose measurement process for a small shaft, vertical orientation determination, and position
parameters obtaining are presented. 2D data is gathered by scanning the generatrix of the part, and valid data is extracted
and saved in arrays. A vertical orientation criterion is proposed to determine whether the part is parallel to the Z-axis of
the coordinate. If not, 2D data will be fixed into a linear equation using least square algorithm. Then orientation
parameters are calculated. Center of Part End (CPE) is selected as feature point of the part, and its position parameters
are extracted form two group of 2D data. Finally, a fast pose measurement device is developed and representative
experiments are carried out. Results show that the measurement method could obtain pose of complex 3D micro parts
fast and accurately, and can meet the demand of microassembly system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823S (2009) https://doi.org/10.1117/12.835560
The contrastive damage experiments of CCD irradiated by 800nm femtosecond laser with the pulse duration of 330fs
and 1064nm laser with the pulse duration of 10ns were studied from the energy density and power density. The failure
problems of the CCD devices irradiated by the two kinds of laser pulses were studied. The experimental results show
that the failure threshold of CCD irradiated by femtosecond laser is 2.3 nJ / cm2and it is 3~4 order lower than that by
nanosecond laser. According to the micro-analysis of CCD, it is found that the damage takes place at the light activated
elements.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823T (2009) https://doi.org/10.1117/12.835558
In this paper, we introduce and demonstrate a new method of reducing speckle noise by multiply holograms. It can
utilize both the phase and amplitude information of the object wave-front. In the superposition process, the phase
surfaces with high signal to noise ratio in the different phase images have been appropriately weighted according to
reconstructed intensity image. We show a theoretical justification of the procedure and experimentally-obtained results
of a USAF-1951 resolution test target, both of which demonstrate that the proposed method could reduce the speckle
noise effectively, and improve the resolution of reconstructed image.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823U (2009) https://doi.org/10.1117/12.836299
Laser Induced Breakdown Spectroscopy (LIBS) has been developing as a promising technique with many
advantages, including on-line, real time, stand off and multi-element detection etc. At present, LIBS application
has involved many areas; more and more researchers have studied LIBS as an in-situ measurement for oceanic
sensing. In this paper, a novel approach for LIBS enhancement has been introduced and used to improve the
sensitivity of underwater detection. In this approach, the replacement reaction assisted with the electric field was
utilized to strengthen the reaction and increase local cations concentration for depositing on the underlay surface.
With the aid of replacement reaction and electric field, the LIBS sensitivity for cations detection underwater was
found to be enhanced significantly, hence the detection limit. The detection limit of 16 ppb was achieved for
copper cations (Cu2+) detection in the water solution of CuSO4. The obtained results suggested that this novel
approach has great potential to be developed as an effective method for cations detection underwater.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823V (2009) https://doi.org/10.1117/12.836230
Carbon monoxide (CO) is a very important gas generated in the industrial process; therefore to implement CO
concentration on-line monitoring is a key factor for industrial process control. Tunable diode laser absorption
spectroscopy (TDLAS) is a high sensitive, high selective and fast trace gas detection technique. With the features of
tunability and narrow linewidth of distributed feedback (DFB) laser and by precisely tuning its wavelength to a single
isolated absorption line of the gas, TDLAS technique can be utilized to accurately perform online gas concentration
monitoring with very high sensitivity. In this paper, a system for online monitoring of CO concentration is developed by
our group employing TDLAS technique. The experimental results are present and discussed in this report. The
characteristics of the system are: the sensitivity, 10ppm; detection accuracy, 0.02%; long term stability, 1%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823W (2009) https://doi.org/10.1117/12.836545
Digital holography combines the advantages of the optical holography and the digital image processing
as a method for recording and reconstructing amplitude and phase of a wave field. Traditional
reconstruction algorithms can only obtain image with the fixed pixel size. By directly discretizing the
Reyleigh-Sommerfeld (RS) integral formula, a new reconstruction algorithm is proposed. Experiment
result shows that the reconstruction pixel size and pixel number can be controlled with the proposed
algorithm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823X (2009) https://doi.org/10.1117/12.835718
Corona is one of important reasons of electrical energy loss in the electric power. According to incomplete statistics,
corona loss electrical energy has achieved two thousands and fifty millions kW.h in our nation every year. Sometimes
corona also can have some disturbance to radio and communication. Therefore to discover and examine corona promptly
has the extremely vital significance for conserving energy and realizing high quality communication. Ultraviolet image
detecting technology is a preferred corona detection method in electric power. It may realize all-weather reliable survey
to corona. The solar blind ultraviolet signal discharged by corona is quite weak. Moreover the ultraviolet image quality
has been affected seriously by the detection system noise. A corona solar blind ultraviolet image processing method is
proposed in this paper. Ultraviolet image has so small target, low contrast image, district characteristic and real-time
demand that it is processed by multi-scale ultraviolet morphology filter technology based on mathematics morphology in
this paper. Results show that the method can stretch image contrast, enhance target and weaken noise. The algorithm is
easy to deal in parallel and it can be realized easily by hardware. It will be accurately demarcated when the condition of
device need to be absolutely measured. The paper proposes a kind of mathematics morphology algorithm. Solar blind
ultraviolet image will be further processed according to temperature and humidity in order to remove the infection of
corona discharge demarcation and solve correct demarcation question when equipment condition need to be absolutely
measured.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823Y (2009) https://doi.org/10.1117/12.835340
A volume holographic grating lens can reconstruct the three-dimensional information by conducting multiple
optical slicing of an object based on Bragg selectivity of the volume holographic grating. In this paper, we employ
the point-spread function of volume holographic imaging system to theoretically analyze its imaging resolution. In
the experiments, the volume holographic gratings are made with a spherical reference (SR) and a planar reference
(PR), respectively, and used as volume holographic imaging lens in our imaging system. The longitudinal and
lateral defocusing characteristics of volume holographic lens with SR and with PR are investigated experimentally
by displacing the interested objects from original reference location, respectively. The effects of the parameters of
the volume holographic lens on the longitudinal and lateral resolution are also discussed. The experimental results
show that increasing the size of the volume holographic lens can improve the depth resolution, and in particular, it
has greater influence on SR VHI. The lateral selectivity of SR VHI is more sensitive than that of PR VHI, and the
Bragg degenerate diffraction of PR VHI on the y axis is obviously observed.
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Zhiqiang Xu, Zhuqing Jiang, Jing Yang, Shiquan Tao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73823Z (2009) https://doi.org/10.1117/12.835565
In this paper the reconstructing images of a tiny object with a volume hologram are investigated by examining the effect
of Bragg mismatch on the quality of imaging. The imaging depth resolutions of the volume holograms with the different
radii are compared. Furthermore, the simultaneous imaging ability of the volume holographic gratings for the different
depths of the object space is demonstrated experimentally by recording two holographic gratings in the same material.
The results show that the depth resolution of the VHI system is 2.1mm in our experiments, in which a volume hologram
is recorded in a 2-mm-thick LiNbO3:Fe:Cu crystal with two recording beams interfering at the wavelength of 532nm,
and is located at a working distance of f=75mm away from the object lens.
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Yan Li, Dayong Wang, Guangjun Wang, Yizhuo Zhang, Changgeng Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738240 (2009) https://doi.org/10.1117/12.835509
A simple method for measurement of temperature field in the region near to the metal plate of the radiator is
demonstrated by using digital holography in the Lensless Fourier transform configuration (LFT). The temperature is
measured within the boundary layer of the convective flow field. The deviation of the temperature produced by this
method, from that obtained by the thermocouple is rather small. It has shown that the method is reasonable and efficient.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738241 (2009) https://doi.org/10.1117/12.834915
Electro-optical testing device is the important technical means to guarantee the operation efficiency of laser range
equipment in complex battle environment. Several important indexes must be tested to ensure the good operation of
pulse laser range equipment, such as the collimation of optical axes, the maximal measuring distance, laser emitting
energy, resolution capability, and laser spot quality. A new kind of testing device is provided in paper. On the one hand,
delay simulating space distance by computer and quasi-laser is used in the term of testing electrical parameters. The
testing method is to collimate the emitted laser beam and disperse the beam into a photometric sphere. Then, emit with a
regulated temporal delay a new beam into the receiver module of the laser range finder, which can realize automatic, fast
and non-disassembly testing to electrical parameters. On the other hand, a new kind of infrared-detecting transforming
device based on up-conversion effect is used in the term of testing laser spot characteristics, which can realize the
capturing of laser spot in real-time to the pulse laser range finder and high-frequency pulse laser measuring range system.
Applications show the testing device is automatically and quickly for many kinds of laser range finder, which has the
characteristics of compact structure, portability, high reliability, which is especially suitable to the application under field
operations.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738242 (2009) https://doi.org/10.1117/12.836546
Laser smoothing technology is employed not only in near field but also in far field in order to make images of scenes
on the ground on the basis of echoes in systems such as 3-D imaging lidar. In this paper, the principle of
superposition after partition is described in detail. Two methods for laser smoothing are introduced, one of which is
lens array, capable of attaining a large area of uniform illumination in far-field, and the other one is birefringent
lenses, suitable to obtain a small area of uniform illumination in far-field. A comparison is made about the
performance characteristics of the two methods from different aspects. This provides a reference about how to
choose smoothing methods to achieve uniform irradiation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738243 (2009) https://doi.org/10.1117/12.835673
A single-laser-shot reflection imaging technique, which can measure the nonlinear optical refraction of the surface of
material possessing limited transparency, is present. Using the model of the reflection 4f coherent imaging system with
phase object, we analyze the phase and amplitude characteristics of the beam reflected from the interface. With the help
of computer and MATLAB, we have done some theoretical analysis and got some conclusions including advantages and
disadvantages. Our model and its corresponding simulation is presented in order to validate our approach.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738244 (2009) https://doi.org/10.1117/12.836667
The laser spot determination is the critical technique in laser detecting systems. Due to atmospheric turbulence and other
factors, the laser spot intensity distributes unevenly in the long-distance measurement. In order to improve the location
precision of the laser spot detection, an improved sub-pixel algorithm based on Zernike moments is presented in this
paper with theoretical analysis. The experimental results of the proposed algorithm with CCD image test are also given
and compared with that of four conventional algorithms including gravity model, Hough transform, circle fitting, and
spatial moment operators. The comparative results demonstrate that the improved algorithm based on Zernike moments
has the virtue of higher measuring precision. The stability and interference suppression ability are also improved. The
proposed algorithm has already been applied into the processing of our laser detecting system, which can also play an
important role in automatic recognition, etc.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738245 (2009) https://doi.org/10.1117/12.835027
A high energy high peak power flash-lamp pumped pulsed Nd:YAG solid-state laser is investigated in this paper. The
symmetrical resonator laser is developed and rated at single pulse energy 60J, peak power 30KW with beam parameter
product 2mm.mrad. The total system electro-optics efficiency of the lamp-pumped YAG laser is as high as 3.1% with
pulse width tunable between 0.05-2ms. The results are consistent with the theoretical analysis and simulation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738246 (2009) https://doi.org/10.1117/12.834160
A photon communication system based on orbital angular momentum (OAM)-carrying beams is studied. We
compartmentalize the atmospheric aberration into tilt,coma, astigmatism as well as defous. We numerically analyze the
effects of tilt on the orbital angular momentum of communication beams and find that the tilt aberration can induce the
noisy OAM. With the increasing of parameters P, L, the probability of initial OAM goes down while the effective
number of noise OAM increases. At the same time, the peaks of the induced OAM probability (max-probability) are
different as the P, L, changes. The increase of zenith angle damages the probability and leads to noisy OAM. This
can also be applied to the impact of refractive index structure parameter. We also numerically analyze the effects which
receiving-radius puts on the receiving probability of initial OAM through tilt aberration. Under the influence of tilt, the
receiving probability of previous orbital angular momentum slashs with the receiving-radius becoming large.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738247 (2009) https://doi.org/10.1117/12.836953
We recently proposed a metric that incorporates scintillation reduction and beam spread for
evaluating the performance of a partially coherent laser beam propagating through atmospheric
turbulence. The metric was evaluated relative to other measures such as probability of fade and
number of fades and it was verified that the metric can be used to find the parameters for optimal or
near-optimal beam performance. In this work, we review the performance metric and develop
analytical expressions as a function of the source beam curvature F0 and other link parameters. The
behavior of the metric as a function of F0 is investigated for different link scenarios. A wave
(physical) optics simulation is also implemented and its results compare favorably with the analytical
results.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738248 (2009) https://doi.org/10.1117/12.835672
Several heavy mental substituted phthalocyanines are effective materials for optical limiters in the visible and near
IR. Lead-tetrakis (cumplphenoxy) phthalocyanine [PbPc (CP)4] was identified as especially attractive for optical
limiting applications. In the paper, we investigate the third-order optical nonlinearities of [PbPc (CP) 4] at 600nm by
a nonlinear-imaging technique with a phase object (NIT-PO). The theoretical simulation fit well with experimental
results.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738249 (2009) https://doi.org/10.1117/12.835282
Dynamic detection of polarization states is very important for laser polarization coding guidance systems. In this paper, a
set of dynamic polarization decoding and detection system used in laser polarization coding guidance was designed.
Detection process of the normal incident polarized light is analyzed with Jones Matrix; the system can effectively detect
changes in polarization. Influence of non-normal incident light on performance of polarization decoding and detection
system is studied; analysis showed that changes in incident angle will have a negative impact on measure results, the
non-normal incident influence is mainly caused by second-order birefringence and polarization sensitivity effect
generated in the phase delay and beam splitter prism. Combined with Fresnel formula, decoding errors of linearly
polarized light, elliptically polarized light and circularly polarized light with different incident angles into the detector
are calculated respectively, the results show that the decoding errors increase with increase of incident angle. Decoding
errors have relations with geometry parameters, material refractive index of wave plate, polarization beam splitting
prism. Decoding error can be reduced by using thin low-order wave-plate. Simulation of detection of polarized light with
different incident angle confirmed the corresponding conclusions.
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Chang Wei Li, Yu Xiao Wang, Min Shui, Xiao Jin, Jun Yi Yang, Xue Ru Zhang, Kun Yang, Ying Lin Song
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824A (2009) https://doi.org/10.1117/12.835499
A nonlinear image technique for characterization of the optical nonlinearities is used to investigate the solid
semiconductor ZnSe at 600 nm. The method based on a 4f nonlinear image technique with a phase object is used to
obtain the diffraction pattern of the nonlinear filter in solid ZnSe located at the Fourier plane by a CCD camera. The
nonlinear absorption coefficient and nonlinear refraction index were both obtained by fitting the nonlinear image. Good
agreement between the experiment data and the simulated result are obtained indicating a sensitive and powerful method
for nonlinear optical measurements.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824B (2009) https://doi.org/10.1117/12.834561
In this paper, the weighted fractional Fourier transform with dilation parameter (N-PFRFT) is proposed as the weighted
combination of the first four integer-order ordinary Fourier transforms. This N-PFRFT is an extension of four-item
weighted fractional Fourier transform (N-PFRFT) defined by Shih[1] and it owns four free parameters in the
weight coefficients besides the order of the fractional Fourier transform. A novel image encryption algorithm is
presented by the N-PFRFT.The method owns more secret keys than the encryption methods operated by other
fractional Fourier transforms without any increase of the computational complexity. On the other hand, the image
still can't be decrypted correctly even though the order of FRFT which is treated as a secret key is known. So do
the four free parameters. Therefore, both the order parameter and the vector parameter can be chosen in the real
domain to improve the security of the encryption method. Digital simulations are presented to verify the more
validity and efficiency of the algorithm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824C (2009) https://doi.org/10.1117/12.836547
A line imaging ladar sensor using linear diode laser array and linear avalanche photodiode (APD) array is developed for
precise terminal guidance and intelligent proximity fuzing applications. The detection principle of line imaging ladar is
discussed in detail, and design method of the line imaging ladar sensor system is given. Taking military tank target as
example, simulated tank height and intensity images are obtained by the line imaging ladar simulation system. The
subsystems of line imaging ladar sensor including transmitter and receiver are designed. Multi-pulse coherent algorithm
and correlation detection method are adopted to improve the SNR of echo and to estimate time-of-flight, respectively.
Experiment results show that the power SNR can be improved by N (number of coherent average) times and the
maximum range error is 0.25 m. A few of joint transform correlation (JTC) techniques are discussed to improve noncooperative
target recognition capability in height image with complex background. Simulation results show that binary
JTC, non-zero-order modified fringe-adjusted JTC and non-zero-order amplitude-modulated JTC can improve the target
recognition performance effectively.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824D (2009) https://doi.org/10.1117/12.835669
Using time-resolved pump-probe system based on nonlinear image technique with phase object, we determine the
rotational lifetime of toluene with 19-ps laser pulse at 532 nm. The system can be applied to both degenerate and
non-degenerate beams in any polarization states. The proposed method is advantageous and imposes a lower stress
in the cases of fragile materials, since a single shot of laser pulse is enough for the definition of their nonlinear
refractive indices and absorption coefficients. Advantages of this scheme are relative ease of producing the steady
probe beam with top-hat profile. The coupling theory of the pump beam and the probe beam in perpendicular linear
polarizations states is used to interpret the experimental results. With the help of coupling equations we numerically
fitted our experimental results. Good agreement is obtained between the theory and the experiment. Additionally, we
derive the rotational lifetime of toluene τrot=4.8 ps with the help of theoretical fit.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824E (2009) https://doi.org/10.1117/12.836854
Based on the reflectance of saturable absorber depended on the optical intensity and the interference theory, we
investigate the reflectance bandwidth characteristic of the semiconductor saturable absorber mirror (SESAM). Two
kinds of SESAMs, one of which satisfies the antiresonance condition, and the other does not, are contrastively studied in
mode-locked Nd:YAG lasers. Results show that stabilized continuous-wave mode-locking can also be obtained in
picosecond regime by the SESAM, which dose not fulfill the antiresonance condition, as good as the results obtained
using a mature commercial SESAM satisfying the antiresonance condition. Because the bandwidth of picosecond regime
mode-locked pulse is not broad; therefore a broad bandwidth and a minimal group velocity are not necessary. Without
considering the limit of the antiresonance condition, the difficulty of designing and growing SESAMs will be decreased
significantly and there will be more freedom in the macroscopic parameters.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824F (2009) https://doi.org/10.1117/12.835601
The bacteriological microscopic examination of sputum smear for tuberculosis is the most important means of diagnosis
and experiments for tuberculosis. Through micro-imaging systems, machine vision systems, digital image processing
and computer pattern recognition technology, dynamic intelligent recognition and counting of TB-DNA could be realized.
However, the dynamic range of CCD image sensor is limited. The information of TB-DNA could not be fully recorded on
microscopic image. In this paper, an effective method to extend the image dynamic range through merging multiple
exposure images is proposed. The microscopic images of the same scene with different exposure are taken by rotating
the disk-shaped optical grads attenuator that installed under the objective lens of microscopic system to control the
illumination. These different exposure images are processed firstly to get irradiance response function of the imaging
system, and then the high dynamic range microscopic image (HDRMI) could be obtained. Through the mapping
algorithm the dynamic range of HDRMI is compressed in order to been displayed on the general display devices, which
not only highlight the feature information of bacillus but also maintain the overall contrast of original microscopic
image. The method proposed can effectively express the image information of the bright areas and dark areas in the
scenes and enhance the image details and color characteristics. The quality of micro-imaging systems is improved. It is
proved that the method proposed in the paper can enhance the resolution and stability of the TB image recognition
through the experiment.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824G (2009) https://doi.org/10.1117/12.836569
In robotic remanufacturing measurement system, the 3D laser scanner is arranged by the robot and the object scanned is
mounted on a turntable. This paper deals with the method of calibrating the relationship between the scanner coordinate
and the robot Tool0 and furthermore locating the center axis of the turntable. The data of Tool0 can be directly obtained
denoting its relationship with the robot base coordinate. So, the new methods of coordinate's transformation are
effectively developed. Moreover some motivated experiments and optimized programs are designed for realizing process
stabilization and reliability. This paper detailed explains the basic algorithm theory, practical operation instructions, the
experiment data analysis, and etc. Theory deduction and experiments show the new methods are reasonable and
efficient.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824H (2009) https://doi.org/10.1117/12.835118
Surface enhanced Raman spectroscopy (SERS) can provide information of internal structures and chemical components
from different kinds of samples. Laser scanning confocal microscopy (LSCM) can show morphologic information of
samples by high-resolution optical images with different focal planes. In this paper, the dynamic variation of cancer cells
(HELA cells) in the apoptosis was first studied by combining SERS and LSCM. After gold nanoparticles (GNPS) uptake,
HELA cells were divided into two groups, and were respectively studied at six different time points of cell apoptosis
period by SERS and LSCM. The LSCM images of HELA cells obtained at different time points were analyzed, and the
morphology varieties of HELA cells apoptosis were obtained. It suggests that HELA cells apoptosis gradually in the
apoptosis period until they died. In addition, Raman spectra of HELA cells measured at different time points were also
compared. It shows that some Raman signal peaks shift, and FWHM of Raman peaks change too. The variation of
internal structures and chemical constituents were analyzed according to the shifts and FWHM of the Raman peaks. The
internal dynamic information and morphologic varieties from HELA cells apoptosis gained by combining SERS and
LSCM will make us to understand cancer cell apoptosis throughly.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824I (2009) https://doi.org/10.1117/12.836353
Development of 2 micron solid-state lasers has attracted a great deal of attention in recent years, because 2 micron lasers
have many potential applications in various fields, such as remote sensing, medical application, laser radar, and optical
communication in space. The MOPA system is an effective way to obtain high energy and good frequency and beam
qualities which are required in coherent lidars. The traditional MOPA systems use injection seeding technology to obtain
narrow linewidth and high power/energy laser output at the same time. Feedback control makes systems of injection
seeding MOPA more complicated in applications. Thanks to the fast development of fiber fabrication technology,
various fibers working in 2 micron region are commercially available. Two micron fiber MOPA systems are more
attractive for researchers due to their compactness, good thermal dissipation and high efficiency. A 2 micron
master-oscillator-power-amplifier (MOPA) system was built. The seed oscillator was a plano-concave straight cavity.
YAP Laser crystals with 4% and 5% thulium-doped concentration were used in our experiments. 1.5% and 3% output
couplers were used. 442mW output power at 1.99μm was obtained with the 4% thulium-doped Tm:YAP crystal when
the launched pumping power is 2.7W. The seed oscillator is coupled into a 4.5-meter-long double-cladding LMA Tm3+
and Al3+ co-doped fiber. The fiber diameter is 25 μm and NA is 0.1. 6.13W CW amplified output signal power was
obtained when the launched pumping power was 60W.
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Pengfei Wang, Dieyan Chen, Wanyun Ma, Hongxin Wu, Liang Ji, Jialin Sun, Danyu Lv, Lu Zhang, Ying Li, et al.
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824J (2009) https://doi.org/10.1117/12.834098
Contemporary biology has developed into the era of cell biology and molecular biology, and people try to study the
mechanism of all kinds of biological phenomena at the microcosmic level now. Accurate description of the
microstructure of biological samples is exigent need from many biomedical experiments. This paper introduces a method
for 3-dimensional quantitative observation on the microstructure of vital biological samples based on two photon laser
scanning microscopy (TPLSM). TPLSM is a novel kind of fluorescence microscopy, which has excellence in its low
optical damage, high resolution, deep penetration depth and suitability for 3-dimensional (3D) imaging. Fluorescent
stained samples were observed by TPLSM, and afterward the original shapes of them were obtained through 3D image
reconstruction. The spatial distribution of all objects in samples as well as their volumes could be derived by image
segmentation and mathematic calculation. Thus the 3-dimensionally and quantitatively depicted microstructure of the
samples was finally derived. We applied this method to quantitative analysis of the spatial distribution of chromosomes
in meiotic mouse oocytes at metaphase, and wonderful results came out last.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824K (2009) https://doi.org/10.1117/12.835374
Phase object exists widely in nature, such as biological cells, optical components, atmospheric flow field and so on. The
phase detection of objects has great significance in the basic research, nondestructive testing, aerospace, military
weapons and other areas. The usual methods of phase object detection include interference method, grating method,
schlieren method, and phase-contrast method etc. These methods have their own advantages, but they also have some
disadvantages on detecting precision, environmental requirements, cost, detection rate, detection range, detection
linearity in various applications, even the most sophisticated method-phase contrast method mainly used in
microscopic structure, lacks quantitative analysis of the size of the phase of the object and the relationship between the
image contrast and the optical system. In this paper, various phase detection means and the characteristics of different
applications are analyzed based on the optical information processing, and a phase detection system based on optical
filtering is formed. Firstly the frequency spectrum of the phase object is achieved by Fourier transform lens in the
system, then the frequency spectrum is changed reasonably by the filter, at last the image which can represent the phase
distribution through light intensity is achieved by the inverse Fourier transform. The advantages and disadvantages of the
common used filters such as 1/4 wavelength phase filter, high-pass filter and edge filter are analyzed, and their phase
resolution is analyzed in the same optical information processing system, and the factors impacting phase resolution are
pointed out. The paper draws a conclusion that there exists an optimal filter which makes the detect accuracy best for any
application. At last, we discussed how to design an optimal filter through which the ability of the phase testing of optical
information processing system can be improved most.
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Jing Guo, Chun-ping Yang, Mei-ling Kang, Yan Zhang, Jian Wu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824L (2009) https://doi.org/10.1117/12.835019
Laser scattering properties are studied from the rough surface of an ellipsoidal object with the random facet model and the
electromagnetic scattering theory. For actual ellipsoidal objects, such as some airships and air balloons, their lateral correlation lengths
are usually longer than the incident laser wavelength 1.06μm, and their surfaces are conventionally the Lambertian surface. Hence, it
is feasible to analyze their laser scattering properties of the ellipsoidal object by means of the random facet model. In order to evaluate
the scattering, firstly, the ellipsoidal surface is decomposed into many facets according to axial symmetry, then scattered intensity can
be denoted for every facet with a laser scattering model of the Lambertian surface. Secondly, total intensity received by a far-field
optical detective system is gained with the incoherent superposition principle for all facets, where an incident shadow function and a
scattering shadow function are introduced. In the end, far-field angular distribution of the laser scattering intensity is computed and
analyzed under different conditions. The numerical results suggest that the laser backscattering intensity of the ellipsoidal object
increases with its surface roughness. However, if the ellipsoidal surface is correspondingly rough, the incident laser power might be
scattered around.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824M (2009) https://doi.org/10.1117/12.836632
The underwater security system, used in the Qingdao sailboat game of 2008 Olympic
Games, combined multiple underwater cameras with sonar detectors, forms an underwater barrier,
which can observe the movement of suspicious objects and get the underwater video images
continuously and instantly. The lighting system can provide sufficient illumination matched with
target to reach the best imaging result. The whole system with the function of centralized control,
depth measurement, leakage alarm and image processing, is the original equipment in domestic
underwater antiterrorism optical research area.
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Bi-da Su, Su-hui Yang, Jing-feng Wang, Chang-ming Zhao, Hai-yang Zhang, Kang Zhao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824N (2009) https://doi.org/10.1117/12.836407
Micro-Doppler effect and its mathematical model were discussed. The Micro-Doppler effect of vibration and rotation
of moving point target were analyzed. The micro-Doppler frequency shift induced by vibration is simulated and
proceeded by means of the time-frequency analysis. A micro-Doppler Solid-state coherent ladar system for detecting
micro-motion of target was demonstrated to detect the micro-Doppler frequency shifts induced by vibration, complex
micro motion and rotation, and the micro-Doppler frequency shift induced by rotations at 0.2 r/s or vibrations at 0.5Hz
were detected. The information of micro-motion was extracted by the arithmetic of time-frequency analysis. These
results are helpful for target's feature extraction and identification.
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Xi-wen Qiang, Jian-ping Song, Jian-wei Feng, Yan Han
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824O (2009) https://doi.org/10.1117/12.833450
Optical scintillation degrades beam quality as laser beams propagation in the atmosphere and increases rates of code-error
for high-data-rate laser communication in the atmosphere. The scintillated irradiance depends on integrals of atmospheric
turbulence strength along the propagation path. For the shorter path-length and weaker atmospheric turbulence, the
integral is smaller, and the Rytov weak fluctuation theory can solve the problem successfully. However, for longer
path-length and/or stronger atmospheric turbulence strength, multiple scattering events must occur and result in saturation
of irradiance scintillation. The irradiance scintillation of laser beams propagation in the near ground turbulent atmosphere
is investigated for the case of plane wave and spherical wave at various typical atmospheric turbulence strengths and inner
scale of atmospheric turbulence. The dependence of irradiance scintillation on turbulence strength, path-length, and inner
scale is presented for the plane wave case and spherical wave case. The results on plane wave case and spherical wave case
are compared.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824P (2009) https://doi.org/10.1117/12.836594
A detection system based on the laser micro-Doppler effect for detecting
vibration-properties of moving target was developed. This system can detect the
micro-Doppler effect induced by vibration whose order of magnitude is micrometer well.
Frequency domain analysis and time-frequency joint analysis of experimental results showed
that the complex vibration of target can be effectively detected by laser micro-Doppler effect,
and also the application range of laser micro-Doppler effect is further extended. The results of
feature extraction indicate that time-frequency analysis method is fit for the analysis of
time-varying micro-Doppler signal, and the vibration signature of the moving target can be
effectively extracted. The experimental results are shown that it confirms the efficiency of this
system.
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Ben Xu, Kai Yang, Dawei Fang, Jinsong Li, Xiaoyan Li, Jie Huang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824Q (2009) https://doi.org/10.1117/12.836573
Differential Absorption Lidar for detecting atmospheric NO2 (NO2-DIAL) is used extensively for its high precision and
spatial resolution, and the measurement can be done real-time with a wide range. The design of spectrum-dividing
system is a key component of lidar. According to characters of DIAL, such as adjacency of laser wavelength and
weakness of received signal, a set of optic fiber-grating spectrum-dividing system is developed. The system has the
advantages such as high spectral resolution, efficiently divide lidar echo signals in different wavelengths, weak
attenuation, receive and process signals in two channels synchronously, etc. So the SNR of receiving system has
improved.
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Zong-jia Qiu, Si-ying Chen, Yin-chao Zhang, Yu-zhao Wang, Guo-qiang Ni
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824R (2009) https://doi.org/10.1117/12.836669
The information of location and scattering intensity of the target can be detected by lidar system. The physical
characteristics of the target can be retrieved from the scattering intensity. Since the corresponding relationship between
the echo signal intensity and the detection range requires to be measured accurately, a weak signal detection system of
lidar is needed, with strong electromagnetic immunity, high sensitivity and wide dynamic range. In this paper, firstly,
various characteristics of echo signals obtained by aerosol detection lidar, including the signal intensity and frequency
spectrum are analyzed. Secondly, the influencing factors associated with those signal characteristics, such as
photoelectric detector response time and the dynamic range, are also described. At last, a signal-to-noise ratio model for
lidar is established. The influencing factors of the photomultiplier tube shot noise, dark current noise, and background
radiation noise to the final SNR can be assessed. Meanwhile, some effective ways to reduce the interference noise are
discussed.
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Qingju Huang, Honghua Wang, Yunlong Huang, Jiping Lin
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824S (2009) https://doi.org/10.1117/12.835720
In order to study the radiation properties of plasma plume induced by the
interactions between laser and material, the radiation model of plasma plume is
established. The properties of plasma plume induced by ultraviolet plused laser
induced stannum in neon are thoroughly studied. The pulse width of XeCl ultraviolet
laser adopted in the experiment is 10ns, the pulse energy is 90mJ, and the emitted
laser wavelength is 308nm. The pressure of neon ambient gas is tunable between
13Pa and 101.3kPa in the induced chamber. Some color photographs of laser-induced
plasma plume are obtained through swift and synchronous photograph. The
experimental results show that the plasma plume induced by ultraviolet plused laser
induced stannum has different color properties at different areas. Under the low
pressure of 13Pa, the central area of plasma plume is white; the medial area is mixed
color while the outermost area is blue. Each area of the plasma plume decreases
gradually as the gas pressure increases, and the color becomes lighter as the
atmospheric pressure increases. The main excition mechanisms of light-emission of
plasma plume induced by ultraviolet plused laser induced stannumat at different areas are analyzed, and it is believed that there are different light-emission model at
different areas. The excition mechanism of the central area of plasma plume is
bremsstrahlung, as for medial area and outlying region, it is the combination excition
of electrons and ions. The experimental phenomenon that could be explained by the
excition model.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824T (2009) https://doi.org/10.1117/12.835729
A new kind of underwater imaging system is introduced, called double-channel
imaging system, to both improve the detection distance and solve the problem of inherent delay. A
image processing subsystem built on TMS320DM642 DSP is in charge of the two channel videos.
And software algorithm is used to degrade the noise and improve the contrast of the videos before
they are displayed on the monitor. The trails show that images can be acquired at long distance
and very close distance. The quality of the images are greatly improved through the image
processing subsystem.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824U (2009) https://doi.org/10.1117/12.837006
The effects of photostability on the ration of signal to noise in degenerate four-wave mixing (DFWM) using
backward geometry have been first investigated in iodine vapor. Frequency-doubled outputs from a
multi-mode Nd:YAG laser pumped dye laser, which laser dye PM580 was dissolved in the ethanol. Though
phase-match is automatically achieved in the backward folded boxcars geometry, weak signal beams under
the strong background of stray light are hardly detected because of the photostability on the ratio of signal
to noise in DFWM experiments. To solve the problems, a new image processing system for detecting
backward DFWM spectroscopy on iodine vapor is reported. This system is composed of CCD camera,
imaging processing card and the related software. With the help of the detecting system, the focal image
and the beam image of the pump laser's conjugation beam in backward geometry DFWM experiment have
been obtain, in which demonstrated that the backward geometry can't compensate the beam excursion. The
DFWM signal is sensitive to disturb of the environment, which leads to the phase conjugation fidelity
decreased. The study of photostability on the ratio of signal to noise in DFWM experiment is of importance
to trace atom, molecular and radical in combustion diagnosis.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824V (2009) https://doi.org/10.1117/12.837004
Experimental studies of Degenerate four-wave mixing (DFWM) in iodine vapor at atmospheric pressure
and 0℃ and 25℃ are reported. The Laser-induced grating (LIG) studies are carried out by generating the
thermal grating using a pulsed, narrow bandwidth, dye laser .A new image processing system for detecting
forward DFWM spectroscopy on iodine vapor is reported. This system is composed of CCD camera,
imaging processing card and the related software. With the help of the detecting system, phase matching
can be easily achieved in the optical arrangement by crossing the two pumps and the probe as diagonals
linking opposite corners of a rectangular box ,and providing a way to position the PhotoMultiplier Tube
(PMT) . Also it is practical to know the effect of the pointing stability on the optical path by monitoring
facula changing with the laser beam pointing and disturbs of the environment. Finally the effects of
Photostability of dye laser on the ration of signal to noise in DFWM using forward geometries have been
investigated in iodine vapor. This system makes it feasible that the potential application of FG-DFWM is
used as a diagnostic tool in combustion research and environment monitoring.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824W (2009) https://doi.org/10.1117/12.835294
Complete laser wavefront, with phase and intensity, is digitally reconstructed using a speckle-based phase retrieval
method. An automated technique for the full characterization of a laser beam focus and the correction for astigmatism
due to lens rotational misalignment is presented. The technique is also demonstrated in the corrections for illumination
beam tilt and lens defocus in the imaging of the high spatial frequency content in phase objects. The proposed wavefront
alignment technique is fast, precise and robust against aberrations.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824X (2009) https://doi.org/10.1117/12.836333
A double longitudinal mode He-Ne laser with frequency stabilization is proposed. Compared with general methods, such
as Lamb dip, Zeeman splitting and molecule saturation absorption method, this design has some advantages, such as no
piezocrystal or magnetic field, a short frequency-stabilized time, lower cost, and higher frequency stability and
reproducibility. The metal wire is uniformly wrapped on the discharge tube of the laser. When the metal wire is heated
up, the resonant cavity changes with the temperature field around the discharge tube to make the frequency of the laser
to be tuned. The polarizations of the two longitudinal modes from the laser must be orthogonal. The parallelly polarized
light and the vertically polarized light compete with each other, i. e., the parallelly polarized light generates a larger
output power, while, the vertically polarized light correspondingly generates a smaller one, but an equal value is found at
the reference frequencies by automatically adjusting the length of the resonant cavity, due to change of the temperature
in the discharge tube. Consequently the frequencies of the laser are stabilized. In my experiment, an intracavity He-Ne
laser whose length of the resonant cavity is larger than 50mm and smaller than 300mm is selected for the double
longitudinal-mode laser. Influence factors of frequency stability of this laser is only change of the length of the resonant
cavity. The laser includes three stages: mode hopping, transition stage, and modes stability from startup to laser stability.
When this laser is in modes stability, the waveform of heating metal wire is observed to a pulse whose duty is almost
50%, and thermal balances of the resonant cavity mainly rely on discharge tube.
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Lingbing Bu, Xingyou Huang, Nianwen Cao, Jiansong Huang, Li Guan, Kunling Shan
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824Y (2009) https://doi.org/10.1117/12.835730
A Mie-Rayleigh-Raman lidar contains a 200mJ-532nm laser, a 400mm telescope and three detection channels was
constructed in this paper. The three detection channels are Mie channel, Rayleigh channel and Raman channel
respectively. For the intensity of the aerosol backscattering in boundary layers, analog PMT is used in the Mie channel,
from the signal of the analog PMT aerosol extinction can be obtained. The Rayleigh channel detects the Rayleigh
backscattering of the atmospheric molecular, while the Raman channel detects the vibrational Raman signal of N2, which
is 607nm in the system. From the Rayleigh and Raman channels above, air density profile and then the temperature
profile from 5Km to 55Km can be inverted. Primary measurement results were also presented in this paper, to verify the
accuracy of the temperature, comparison was conducted between the lidar measurement and the atmospheric model. The
result showed good agreements. Backscattering coefficient of aerosol in the range of 10Km was also presented in the end,
which indicated the ability of aerosol monitoring.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73824Z (2009) https://doi.org/10.1117/12.836439
A low-cost visible to Near-infrared Imaging Fourier Transform Spectrometer (IFTS) using a beam-folding technique
instead of the spectral folding technique is presented. The retroreflectors are used to replace the plane mirrors to maintain
the optical alignments without the adoption of complex active-alignment measures. Fast-scanning mechanism is adopted
to avoid the high-cost precise-position control system. The interferogram images at sequential sampling points, spectral
images at different wavenumbers and pixel interferograms and spectra of the multimode fiber ends illuminated by a He-
Ne laser and a red LED source respectively, are given. The experimental results show that the IFTS based on the beamfolding
technique can achieve a spectral resolution of ~15cm-1 (~0.5nm) when measuring the bright coherent light source
(the end of a 600 μm fiber coupled with the He-Ne laser). The resolution is mainly limited by the nonlinearity of the
CCD output, the memory size of the PC and the data-transferring speed between the PC and the CCD camera PL-A741.
Preliminary results showed that it is suited to the measurement of bright object sources. This restriction is only due to the
poor performance of the CCD detector array used in the experiment. A fast-scanning visible-Near infrared IFTS for the
objects of low light intensity is feasible when the high-sensitivity CCD camera is adopted.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738250 (2009) https://doi.org/10.1117/12.835661
The output characteristics of fiber lasers built with large-mode-area(LMA) Yb3+-doped double-clad PCF are
experimentally investigated. The gain fiber used in the experimental setup is a LMA Yb3+-doped double-clad PCF,
which contains an Yb3+-doped core of 23μm in diameter and a holy inner clad of 420μm in diameter. In the forwardoutput
configuration the maximum output is 3.43W and the slope efficiency is 34.6%. At the same pump power, the
maximum output in the backward-output configuration is 3.63W and the slope efficiency is 38%. The spectra show that
the fiber lasers in both forward-output and backward-output configurations produce multi-wavelength output in a range
from 1067nm to 1076nm and unstable. Single wavelength output at 1067.5 nm with a FWHM of about 0.2nm is
demonstrated by using a dual-end-output configuration, and a maximum output of 4.25W with a slope efficiency of
44.1% is obtained.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738251 (2009) https://doi.org/10.1117/12.836356
A BP neural network method for the recognition of sea state in laser altimeter is presented in this paper. Sea wave is the
typical stochastic disturbance factor of laser altimeter effecting on low-altitude defense penetration of the intelligent antiship
missiles, the recognition of sea state is studied in order to satisfy the practical needs of flying over the ocean. The
BP neural network fed with the feature vector of laser range-measurement presents the analysis of features and outputs
the estimation result of sea state. The two most distinguishing features are the mean and the variance of the sea echo,
which are extracted from the distance characteristics of sea echo using general theory of statistics. The use of a feedforward
network trained with the back-propagation algorithm is also investigated. The BP neural network is trained
using sample data set to the neural network, and then the BP neural network trained is tested to recognize the sea state
waiting for the classification. The network output shows the recognition accuracy of the model can up to 88%, and the
results of tests show that the BP neural network model for the recognition of sea state is feasible and effective.
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Ping-xue Li, Gang Li, Meng Chen, Da-peng Zhang, Dao-bo Huang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738252 (2009) https://doi.org/10.1117/12.834695
We report an all-solid-state QCW (quasi-continuous-wave) tunable Ti:sapphire laser system from 697nm to 942nm,
which was pumped by an intra-cavity frequency doubling Nd:YAG laser at 532nm. Under the pump power of 18W at
532nm with the repetition rate of 3.9kHz, the average output power of 3.5W at 795nm with an optical conversion
efficiency of 20% was yielded. Through extra-cavity frequency doubling with the nonlinear crystal LBO (LiB3OWe report an all-solid-state QCW (quasi-continuous-wave) tunable Ti:sapphire laser system from 697nm to 942nm,
which was pumped by an intra-cavity frequency doubling Nd:YAG laser at 532nm. Under the pump power of 18W at
532nm with the repetition rate of 3.9kHz, the average output power of 3.5W at 795nm with an optical conversion
efficiency of 20% was yielded. Through extra-cavity frequency doubling with the nonlinear crystal LBO (LiB3O5), cut
for critical type I phase matching (θ=90°, φ=33.2°) at room temperature, tunable second-harmonic generation (SHG)
from 350nm to 465nm was achieved. Through the design of the scan and control system, the whole laser system can be
used to expose the sensitive material under the controlling of computer.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738253 (2009) https://doi.org/10.1117/12.835549
Through the studying on the M-Z interferometer optical system, the authors give a strict contrast analysis of
influence on the steadiness of optical system about optical power, polarization state of laser and optical feedback caused
by different types of beam splitters was made. After adjusting and optimizing the optical system, the authors built a high
a precision vibration measurement of optical system. The system is advantage at the nano-level vibration measurement,
low energy loss and far measuring distance.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738254 (2009) https://doi.org/10.1117/12.837222
Here we present a new optical system for the demands of laser detection and warning
optical system which has a large field-of-view (FOV). A staring imaging laser detecting and
warning system is formed by using 2-channel uncooled infrared focal plane detectors. In this
system, the operating wavelength range is 3~5 microns, and full angle of view is up to 60 degrees.
The largest aperture is 30mm and the photosensitive surface diameter of PIN photoelectric
detector is line array dimension nearly 12mm. And there are also composed of narrow band filters
and signal processing system. A all reflective structure with three elements is used in the object
lens to enlarge FOV and back working range, in the head of which the negative mirror have the
effect of balancing aberration and deviating rays like a prism. And a standard hyperhemisphere
immersion lens with high refractive index is put behind the object lens to satisfy the receiving of a
detector with smaller photosensitive surface. The analyzed results show that the image height is
60mm. It redounds to reduce the power of laser and enhances the distance detected.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738255 (2009) https://doi.org/10.1117/12.835120
In this paper, a single-mode 980nm Yb-doped fiber laser was studied carefully in theory and experiment.
Based on the theoretical research, we chose an appropriate fiber length of 36.5 cm. In the experiment, by
adopting two 0° fiber ends as cavity mirrors, the Yb-doped fiber laser generated a total output power of
1.32 W at 980 nm with the slope efficiency of 75.3%.Through frequency doubling with BIBO crystal, a
total output power of 15 mW at 490.8 nm was obtained. Simultaneously, we produced a 980nm Yb-doped
single-mode pulse fiber laser pumped by an acousto-optics Q-switched Nd:YAG laser. The pulse fiber laser
generated a total average power of 100 mW at 980 nm when the laser pulse was 10 ns at repetition
frequency of 16 kHz.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738256 (2009) https://doi.org/10.1117/12.835663
In modern warfare the performance of weapon system safe and arming device has been put forward higher requirements
because the battlefield environment has become increasingly sophisticated. The safe and arming device should have
good safety of mechanical, electrical, thermal and other aspects and reliable initiation. This paper analyses the laser
initiation of three ways, the laser could initiate the insensitive acceptable charge for the in-line ignition system, so that
the laser in-line ignition can be realized and the laser in-line ignition all electronic safe and arming device is built. Then,
studies the composition and working principle of the laser in-line ignition all electronic safe and arming device and the
various subsystems in-depth. The laser in-line ignition all electronic safe and arming device can be applied to
fixed-point, directional and multi-point initiation and has laid an important foundation of the theory and engineering in
the future weapon system.
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Bo Wang, Jinggao Zheng, Rui Wang, Dieyan Chen, Ping Xue
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738257 (2009) https://doi.org/10.1117/12.836708
Optical coherence tomography (OCT) is a new emerging technique for cross-sectional imaging with high spatial
resolution of micrometer scale. It enables in vivo and non-invasive imaging with no need to contact the sample and is
widely used in biological and clinic application.
In this paper a white-light interference microscope is developed for ultrahigh-resolution full-field optical coherence
tomography (Full-Field OCT) to implement 3D imaging of biological tissue. The experimental setup is based on a
Linnik-type interferometer illuminated by a tungsten halogen lamp via a bundle of fiber. En-face tomographic images
are obtained by demodulation of a combination of interferometric images recorded by a CCD camera. We use a PZT
synchronized with the CCD in the reference arm to get the modulated interferometric image and use a programmed
precisely controlled electric lift stage in the sample arm to get a 3D image. To fulfill the requirement of in vivo
measurement and better match the index of bio-tissue, a pair of high numerical-aperture water immersion microscope
objectives is used. Spatial resolution of 1.8μm×1.12μm (transverse×axial) is achieved owing to the extremely short
coherence length of the light source and optimized compensation of dispersion mismatch. A shot-noise limited detection
sensitivity of 80 dB is obtained at an acquisition time of 5 seconds per image.
The development of a mouse embryo is studied layer by layer with our ultrahigh-resolution full-filed OCT. 3D imaging
of the embryo can be reconstructed by the OCT images. Information of cell shape, centroid, reflectivity, mitosis period
in the development process can be obtained. The variance of the relative reflectivity of an oocyte with time is calculated
as well. It is found that the reflectivity of a living oocyte is much lower than that of a dead. Therefore the reflectivity of
the cytoplasm can be a signal of the cell activity. In fact, all these parameters above could be very useful for
distinguishing the healthy embryos from the morbid, showing high potential for early diagnosis of procreation diseases
at cellular level in clinic. More experimental study is still in progress.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738258 (2009) https://doi.org/10.1117/12.835712
Considering that the high-frequency sub-band can gather most energy of noise by the wavelet decomposition, and the
local variances in edge and noise change inconsistently, the real edges of images are separated from the noise by
choosing an appropriate threshold value in each high-frequency sub-bands of wavelet domain, while the WGMAP
method is used to restore the images. Experimental results show that the images reconstructed by the improved algorithm
reproduce preferably the edge structures of original images; and the signal to noise ratio and the visual effect are
significantly improved.
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Lei Wang, Rongguo Xu, Gaoping Li, Zhaojin Yang, Hongru Yang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738259 (2009) https://doi.org/10.1117/12.835585
A new kind of absolute absorbing high-power laser energy meter is reported in this paper. The energy meter has the
advantage of simpleness, high damage threshold and high precision. The measurement principle, material and the
structure of the energy meter is introduced in the paper. Many different kinds of effectors affect the high-power laser
energy measurement results, these factors including backscatter, heat loss and accuracy of temperature measurement etc.
The paper analyzes all these effectors on the measurement results and the consponding compensating models is given to
enhance the measurement results. Energy meter measurement uncertainty is given in the end.
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Chao Chen, Hong-Ru Yang, Gao-Ping Li, Lei Wu, Yue Shen, Xiao-Peng Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825A (2009) https://doi.org/10.1117/12.836178
A model is currently being developed for simulating images of underwater objects as seen by airborne laser range-gated
(LRG) system. The simulation model is based on physically accurate models of wind generated waves on the sea surface,
and the optical properties of ocean water. It can take as input any digital image and simulate its degradation due to
scattering in water and through the wavy sea surface. This paper describes the model implementation for LRG system
and presents the results of simulations. Simulation results presented here allow the visual evaluation of image quality for
different depth and optical properties of the sea water. These simulations will also allow us to develop optimal strategies
for image processing algorithm of Lidar data.
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Lei Wu, Yue Shen, Gaoping Li, Chao Chen, Hongru Yang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825B (2009) https://doi.org/10.1117/12.835322
There is currently considerable interest in developing electro-optic systems for underwater imaging classification and
identification of submerged objects such as fish shoals and mines. The imaging systems can be divided into active
imaging systems and passive imaging systems. The main feature of the passive imaging systems is that they haven't
illumination sources and depend on lights from targets or surroundings. The active imaging systems use light sources to
illuminate the targets and collect the reflection from the targets. The advantages of active imaging systems over passive
imaging systems are high contrast and without the affection of environment sources. The gated Intensified CCD (ICCD)
cameras are widely used in the active imaging systems because that the laser range-gated (LRG) technology is an
effective way to eliminate the backscattering noise. This paper is devoted to present a model for simulation and
evaluation the performance of gated ICCD cameras for airborne underwater applications. Some simulation results are
presented and discussed.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825C (2009) https://doi.org/10.1117/12.836536
In airborne underwater lidar applications, the reflecting light signal from the sea level is stronger than the one from
the underwater object, the returned signal is decreased with the range as exponential and inverse square law and the
backscattering return is very large. So the dynamic range could reach five to six orders of magnitude in few hundreds of
nanoseconds. Therefore, it is necessary to compress the signal dynamic range to match the range of the digitizing or
processing devices, typically 2 or 3 orders of magnitude, and to eliminate the reflecting light signal from the sea level
and the backscattering. In this paper, we present a Range-Gain-Control Gated PMT method for this problem. The
principal and the design of the Range-Gain-Control Gated PMT system are analyzed and discussed. The experiment
results show that this method can complete the gated and the gain-control of the PMT.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825D (2009) https://doi.org/10.1117/12.836465
As the development of application requirements, to obtain more information of the object is an important direction in
many research fields. Not only 2-D image, but also range and velocity information are required. Hence, the imaging
laser radar technology, which can obtain 3-D or even 4-D information, has been paid more attention. Because of the high
range resolution character and direct Doppler frequency shift measurement function, frequency modulation / continuous
wave (FM/CW) imaging laser radar can be called a 4-D imaging system. The modulated laser floodlights a moving
object, and then the reflecting light is received by optical system and captured by a focal plane array. After obtaining a
series of images, the range-Doppler processing algorithm is performed on the pixels with the same position in all the
images to calculate the object's range and velocity information, and then a 4-D image (angle - angle - range - velocity)
with high accuracy is obtained. This paper describes the FM/CW ladar system's principle, and presents an improved
process algorithm to solve the problem of the traditional range-Doppler algorithm's limit used for high velocity object.
The simulation results in typical object situation prove that the improved process algorithm could increase the velocity
measurement range effectively.
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Yiqin Ji, Deying Chen, Huasong Liu, Zhanshan Wang, Jie Zong, Kewen Zhuang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825E (2009) https://doi.org/10.1117/12.836975
In the laser systems for measurement and so on, like gyro; in its laser cavity or path, it
makes use of the optical components which need very high performances, like low loss, low
scatter, low reflection, low absorption and high transmittance. In this article, we design and
manufacture the 632.8nm(He-Ne laser) low loss AR (LLAR) on crystal quartz, the results show
this LLAR have the total loss is about 30ppm and have high uniformity, the fluctuations of the
total loss mainly from the surface contamination and the inner defects of crystal material.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825F (2009) https://doi.org/10.1117/12.835225
The beam with orbital angular momentum is a present domestic and foreign research key direction. Its application and
development will bring the profound influence in the optical communications field. At the same time, light's orbital
angular momentum promises potential applications in both classical and quantum optical communication. The research
progress of the beam with orbital angular momentum and encoding information as light's OAM for free-space optical
communication were reviewed in this article, the existing design method, mechanism and description methods of
encoding information as light's OAM were discussed. In quantum communication, qudits can be encoded in photons
using their OAM for creating high-dimensional entanglement based on entangled photon pairs from SPDC. In this paper,
light's OAM is used as information carrier for classical and quantum communication, which is promising to ensures the
security of atmospheric laser communication, improves the density and precision of information transmission. It is
apparent that an efficient way to measure the orbital angular momentum of individual photons and light beams with
good efficiency would be of potentially great importance for optical communications and quantum information. In view
of the above, the measurements of orbital angular momentum of individual photons and light beams are analyzed and
discussed in detail.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825G (2009) https://doi.org/10.1117/12.836190
In this paper, 3 types of laser beam scanner are introduced. One is transmissive beam scanner, which is composed of
convex and concave microlens arrays (MLAs). By moving the concave lens in the plane vertical to the optical axis, the
incident beam can be deflected in two dimensions. Those two kinds of MLAs are fabricated by thermal reflow and
replication process. A set of mechanical scanner frame is fabricated with the two MLAs assembling in it. The testing
result shown that the beam deflection angles are 9.5° and 9.6°, in the 2 dimension(2D) with the scanning frequency of 2
HZ and 8 HZ, respectively. The second type of laser beam scanner is actuated by voice coil actuators (VCAs). Based on
ANSOFT MAXWELL software, we have designed VCAs with small size and large force which have optimized
properties. The model of VCAs is built using AutoCAD and is analyzed by Ansoft maxwell. According to the simulation
results, high performance VCAs are fabricated and tested. The result is that the force of the VCAs is 6.39N/A, and the
displacement is ±2.5mm. A set up of beam scanner is fabricated and actuated by the designed VCAs. The testing result
shown that the two dimensional scanning angle is 15° and 10° respectively at the frequency of 60HZ. The two
dimensional scanning angle is 8.3° and 6° respectively at the frequency of 100HZ. The third type of scanner is actuated
by amplified piezoelectric actuators (APAs). The scanning mirror is actuated by the piezoelectric (PZ) actuators with the
scanning frequency of 700HZ, 250HZ and 87HZ respectively. The optical scanning angle is ±0.5° at the three
frequencies.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 73825I (2009) https://doi.org/10.1117/12.835714
The 4f coherent imaging system with phase object (PO) is a new method to measure the third-order nonlinearity. The
essential of the measurement is using a diaphragm with phase object to modulate the nonlinear phase shift in the
nonlinear sample, which is placed at the Fourier plane of the 4f system, to change of the amplitude of the electric field in
the image plane. In this paper Fractional Fourier Transform (FRFT) is applied to the 4f coherent imaging system for the
third-order nonlinear refraction measurements. With the help of Fresnel diffraction, we obtain FRFT using the
single-lens system, Lohmann type system. The improved measurement system is obtained with FRFT in place of FT
after the beam pass through the sample. We numerically analyze the effects of fractional order on the diffraction image
of the improved nonlinear measurement system. Comparing with the original 4f system, when the fractional order a is
0.4 the sensitivity which is measured by ΔT (ΔT is proportional to the fluence inside and outside of PO on the image
plane) is improved.
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