Under the high energy irradiation, the charges (even little) of molecules of polymer can cause the physical and chemical
characteristics evident changes of polymer. The physics and chemical mechanisms which are responsible for radiation induced loss
was analyzed. The radiation damage of polymethylmethacrylate (PMMA), Polystyrene PS and polycarbonate (PC) optical fiber
under γ-ray irradiation was researched experimentally. The visible light transmission of the POF under different irradiation dose
was measured. The results indicated that the radiation damage of three kinds of POF was wavelength-dependent. Under lower dose
below 1KGy, the transmission rate decreased identical in the whole visible light range. When the irradiation dose exceeded 5KGy, the
transmission rate reduced obviously, and the recovery indicated that the visible light transmission rate of the POF in the range of
400nm to 500nm comparing with 600nm to 800nm, decreased seriously under the irradiation dose exceeded 5kGy. The transmission
rate of both PMMA and PC have an evident peak value at the range 550nm-650m, and that of PS has a wide band at the range
500-700nm. We also measured the recovery of three kinds of POF under different irradiation dose by measuring several times the POF
after stopping irradiating.
The Step-index plastic optical fiber (SIPOF) bandwidth calculation model is given. The model includes not only the modal delay but also the attenuation and mode coupling effects. the numerical solution of the power flow equation in Fourier domain which is the main equation in this model is reported. This solution is based on Crank-Nicholson implicit difference method. The frequency response function and bandwidth of four kinds of SIPOFS with different Numerical aperture is researched. The frequency response function and bandwidth under selective excitation is numerically calculated. The results imply that the selective excitation of SIPOF increased effectively the fiber bandwidth. Calculated results are useful for practical application of plastic optical fiber.
As a relay optical component, fiber optic taper has become more important and more widely used in the integrated taper assembly image intensified sensors for military and medical imaging application. However, the method for evaluating the quality of output images from the fiber optic taper is few. In this article, the Modulation Transfer Function (MTF) is introduced and measured to evaluate the image quality of fiber optic taper. Because fiber optic taper is of a mosaic array architecture, there are some new problems need to be resolved in defining MTF of it. And there also should be some special requirements in MTF measurement. Two methods including edge scanning and point imaging analyzing are introduced in measuring MTF of fiber optic taper, in which the incident light, scanning step and scanning range are specially limited. Experiments show that the results of the measurements consist with the theoretical analysis simulated by computer. And the spatial averaged MTF of fiber optic taper has been gotten by two means. It is concluded that the MTF value measured by point imaging is always some higher than measured by edge scanning, because the point imaging is more weakly effected by the fiber arrangement in taper.
In this paper, rare earth (Eu3+, Sm3+) binary chelates with hexafluoroacetylacetone(HFA), thenoyltri fluoroacetylacetone (HTTA), and dibenzoylmethide(DBM) were synthesized, respectively. Then the fluorescence properties of the chelates Eu(TTA)3, Eu(HFA)3, Eu(DBM)3, Sm(TTA)3, Sm(HFA)3 and Sm(DBM)3 in benzene were investigated. It was found that the fluorescence peak at 614nm related to the transition of 5D0->7F2 of Eu3+ was the strongest in Eu(TTA)3. Based on this, the concentration (between 0.05-0.5wt.%) influence of Eu(TTA)3 on fluorescence intensity in Eu(TTA)3-doped PMMA was studied. The results showed the fluorescence intensity increases with Eu(TTA)3 concentrations except that no fluorescence peak was detected for 0.05wt.% Eu(TTA)3-doped sample. However, the sharp fluorescence peak accidentally occurs at 614nm when 0.04wt% Eu(TTA)3 and 0.04wt% Sm(TTA)3 were co-doped in PMMA. Further investigation revealed that similar fluorescence enhancement occurred for all samples co-doped with Eu(TTA)3 and Sm(TTA)3. It indicated that Sm(TTA)3 has a strong sensitization effect on the fluorescence of Eu(TTA)3. Besides, it was also found the sensitization effect could be decreased with the increasing Sm(TTA)3 concentrations for a fixed Eu(TTA)3-doped content. Finally, two possible energy transfer mechanisms were analysed.
Fiber optic taper has been used more and more widely as a relay optical component in the integrated taper assembly image intensified sensors for military and medical imaging application. In this paper, the transmission characteristic of energy in the taper is analyzed, and following the generalized definition of the modulation transfer function for sampled imaging system, a spatial averaged impulse response and a corresponding MTF component that are inherent in the sampling process of taper are deduced, and the mathematical model for evaluating the modulation transfer function of fiber optic taper is built. Finally, the dynamic and static modulation transfer function curves simulated by computer have been exhibited.
In this paper, a measuring method utilizing Modulation Transfer Function (MTF) to evaluate the imaging performance of fiber optical plates, is proposed. As a kind of relay optical component in optical imaging systems, optical fiber transfer image plates have become more important and more available. By digital simulating the discrete MTF values, algorithm for MTF measure of fiber plates is studied. And MTF experimental results for the performance evaluation of fiber plates with knife-edge effect compared CCD test, are also discussed.
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