Photocoagulators are one of the most popular laser devices in medicine. Due to different kind of interaction of particular
wavelength range of laser light with live tissues, sources of laser radiation which can cover as much as possible of visible
spectrum are still very wanted (see [1,2]). In last years it also can be observed the intensive developing works on new
photocoagulation technique called “micropulse coagulation” [3,4]. The most critical feature of lasers for micropulse
coagulation is the possibility of fast switching between two selected laser power values. It seems that the good proposal
for these applications can be ion laser filled with argon-krypton mixture. Authors previously have indicated the
possibility of improvement of generation conditions in this type of laser in presence of buffer gases [5,6] and with use
developed by authors pulse supply regime [7,8]. These improvements allow to obtain output power values of most
important argon and krypton laser lines in laser filled with mixture of both gases, similar to values available in laser
filled with pure gases. Presented in this paper the following researches are concerned on verification of possibilities of
use of the developed laser system in photocoagulation with possibility of use of the laser system in micropulse
coagulation technique.
In the previous our paper we have presented measurement results of the phenomenon of argon additions influence on
output parameters of krypton ion lasers. In that paper we have described that small argon admixtures to the krypton
discharge increase the laser output power of several krypton laser lines. In actual paper we present following
measurement results of this phenomenon. We have observed that neon admixtures cause much stronger effect on krypton
laser lines than we have previously observed with argon admixtures. We have also observed the positive influence of
neon additions on generation conditions of argon laser lines. The magnitude of this effect is weaker than influence
observed with krypton laser lines however the way of the effect is identical. This confirms our explanation of this
phenomenon described in. Results presented in actual paper were performed in wide range of mixture compositions,
gas pressures and discharge current values for several argon and krypton laser lines.
Argon ion lasers can generate several strong laser lines in short wavelength region of visible spectrum (green and blue
light). Krypton ones offer the generation of laser lines in long wavelength region (red and yellow light). Both gases have
complementary generation ranges thus ion lasers filled with mixture of argon and krypton are attractive laser sources for
many applications. In most of these applications the only one laser line selected with dispersion element within the
resonator are used at one time. After removing the dispersion element the simultaneous generation of many wavelengths
is possible. Unfortunately in this working mode of ion lasers the negative effect of competition between laser lines
appears. The effect has the most significant influence on the generation of yellow Kr II 568 nm line which is very needed
for some applications due to small number of other available strong laser sources for this light range. Generation
conditions of this line is strongly hampered when ion laser simultaneously generates other laser lines thus in this laser
working mode this laser line completely disappears. We have observed the exact reason of this effect and we have
described the way to improve laser generation conditions of Kr II 568 nm line which makes possible to obtain the laser
generation of this line simultaneously with other laser lines.
Ion gas lasers filled with pure argon or krypton are often used in medicine. The number of possible medical laser
applications are still increasing. Every type of application requires specific wavelength range. Due to number of
available laser wavelengths of argon and krypton lasers, laser filled with mixture of both gases could be interesting
universal medical laser source. However output power value of some interesting in medical point of view laser
wavelengths may be insufficient in laser filled with mixture. Developed by authors quasi-continuous ion laser supply
regime in connection with observed and described by authors the effect of laser power increase in presence of noble gas
admixtures allows to achieve laser power satisfactory for certain medical applications but unavailable in typical ion
lasers operated with standard continuous power supply regime.
In this paper authors will present the phenomenon of advantageous influence of noble gas additions on the output
parameters of krypton ion lasers. Authors have observed that small additions of argon to the krypton discharge causes
increase of laser output power of certain krypton laser lines. The power change depends on laser line wavelength,
mixture composition, gas pressure and discharge current values. Authors will present measurement results and
explanation of this phenomenon.
This paper is a continuation of our earlier works on remote measurement tools for supporting the research on novel photonic materials. The scope of this particular work encompasses especially a brief review of present exemplary implementations of remote access methods to measurement equipment, followed by proposing a design for a system management web-based application and related databases, selection of optimal software technologies and their implementation. Case-study for a real-time working system has been developed and proposed, which utilizes apparatus available at three collaborating laboratories located at Warsaw University of Technology and dedicated to photonics research.
In terms of maximal laser output power, the optimum gas pressure in the ion laser tubes depends on a wavelength of the
generated spectral line. In order to control the gas pressure we introduced a simple and effective method of gas pumping
from the laser tube to an additional reservoir. This method could be well employed in commercially available ion lasers.
In many applications of ion gas lasers the laser beam is used for specified short periods of time. For these applications
laser systems are typically equipped with mechanical shutter. In consequence of this regime of laser beam modulation
the peak output power of laser pulses are equal to constant output power generated by laser. Results of our experiments
described in 1 shows that in pulse mode of supplying discharge current it is possible to obtain significant increase of peak
value of laser output power in comparison with laser output power generated in CW operation (without current
modulation).
In this paper we present results of our following experiments on pulse supply of ion laser filled with argon-krypton
mixture. For this laser operates in pulse regime we have observed the significant - up to 3.5 times - increase of peak
laser output power. This effect was especially strong in the UV range. This paper anwe measured in far field the sigxture
percentage on the output power of individual Ar and Kr spectral lines in pulse operation. The research suggests that the
most significant effect results from different gas pumping rate of the mixture components in the discharge path.a
Significant progress observed in last years in structure and technology of ion laser discharge tubes created new possibilities of the continuous generation of the ultraviolet radiation. Segmented metal-ceramic laser discharge tube was used in our experiments. CW generation of 3 new UV lines in double ionized argon and krypton was observed. Generation of two of these lines (Ar III, λ=350.4 nm and Kr III, λ=330.4 nm) was unknown up today even in high current pulse operation. The shortest (λ=324.8 nm) Kr III line, well known in pulse mode but unknown in CW operation is particularly important. Relatively low threshold current and comparable with known Kr III (337 nm) output power level makes easy its application. Laser UV operation on the mixture of two most important, active gases Ar and Kr were studied. Simultaneous generation of the all laser lines of Ar III and Kr III was achieved. For the optimal mixture composition relatively high power generation of 10 laser lines in a wide spectral range 324 - 363 nm were obtained. Preliminary experiments on determining the influence of high ionization potential inert gases (Ne, He) on the UV generation in the argon were carried out. Advantageous influence of Ne results on the distinct increasing of the laser power and similar distinct lowering the threshold current of the generation was observed.
Argon and krypton ion lasers work typically in CW (continuous wave) mode. In many of applications, the continuous operation of ion lasers is not required. Presented in this article laser power supply makes possible to operate in two regimes: continuous and quasi-continuous (multi-pulse). In multi-pulse operation the most of output power limits for continuous regime was overcame. This allowed increasing the laser output power considerably. Particularly excellent results were obtained for laser tube filled with Ar-Kr mixture and operating in UV range. The main phenomenon deciding on output laser power increasing in pulse and multi-pulse operation is minimization of harmful effects of gas pumping. Possibility of multi-pulse operation creates new advantages of ion lasers and extends range of its applications.
In this paper a new construction and technology of argon laser discharge tube is presented. The discharge capillary consists of silicon carbide discs brazed to copper segments. Basic parameters of the new tube (laser output power and magnitude of a gas pumping effect) were measured. These parameters are better in comparison to classical metal-ceramic laser tube.
The influence of the 3He isotope as a buffer gas on the operating characteristics of the He-Ne and He-Kr hollow cathode lasers is studied. A comparison of the laser output power on the NeI 1.15 micrometer line (2s2 - 2p4 transition) and KrII 469.4 nm line (6s 4P5/2 - 5p 4D7/2 transition) in 3He-noble gas and 4He- noble gas mixtures is made. An increase of 4 times in the case of 3He-Ne gas mixture and of 33% in the case 3He-Kr gas mixture is observed. The plasma kinetics is analyzed and it is shown that the observed increase of the laser parameters is due to the following changes in particle kinetics: (1) increased rate constant for the excitation transfer reaction; (2) increased density of the He (2 3S1) metastable atoms; (3) decreased population rate of the NeI lower laser level 2p4; (4) decreased density of the Ne (1s3, 1s5) metastable atoms and (5) increased density of the Kr ground state ions. The main reasons for that are the higher mean relative velocity of the colliding particles and the higher rate of electron cooling in 3He-noble gas plasma. Peak powers of 10 W and 1.5 W and small signal gains of 85%/m and 64%/m are measured for the blue and violet KrII lines, respectively, from 21 cm active length.
The influence of 3He isotope on laser performance of a sputtered segmented hollow cathode discharge He-Cu ion laser oscillating on 780.8 nm transition is presented. At low currents the laser power and small-signal gain are higher for 3He than for 4He. At higher discharge currents the laser parameters are similar both isotopes. However, due to lower discharge voltage for 3He, the same laser output power is obtained at small electrical input power.
In this paper we repot efficient laser oscillation on the IR 840.4 nm Ag II transition in a He-Ag laser with high voltage 3 mm I.D. and 20 cm long helical hollow cathode. Small- signal gain coefficient of about 60 percent/m for that line was measured at the discharge current 2 A. A similar gain was reported in a conventional HCD at about 10 times higher linear discharge current density. The Ag II 840.4 nm laser transition was found to be homogeneously broadened.
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