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RSS2002 Vol. 26, No. 1
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2002, 26(1): 1-3,8.
[Abstract]
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Abstract:
The 40Cr steel has been surface-alloyed with a pre deposited carbon powder layer by laser beam.White cast iron is obtained on the surface of the sample with a depth of 0.25～0.35mm.The microstructure of the melted zone is pre-dendrite and eutectic ledeburite whose size is obviously refined by the rapid quench.Its micro hardness can get up to 1200HV0.3.The microstructure of the heat-affected zone is martensite with two sub-layers,one of which is pin-like martensite and the other,no-pin martensite.It indicates that the higher the scanning speed and power density,the smaller the grain,and therefore the higher the micro hardness.The wear test shows that the wear resistance of the specimens has been encreased by 50% than the general quenched samples.
The 40Cr steel has been surface-alloyed with a pre deposited carbon powder layer by laser beam.White cast iron is obtained on the surface of the sample with a depth of 0.25～0.35mm.The microstructure of the melted zone is pre-dendrite and eutectic ledeburite whose size is obviously refined by the rapid quench.Its micro hardness can get up to 1200HV0.3.The microstructure of the heat-affected zone is martensite with two sub-layers,one of which is pin-like martensite and the other,no-pin martensite.It indicates that the higher the scanning speed and power density,the smaller the grain,and therefore the higher the micro hardness.The wear test shows that the wear resistance of the specimens has been encreased by 50% than the general quenched samples.
2002, 26(1): 4-8.
Abstract:
Because of the vibration of the satellite,the bit error rate(BER) will be influenced in a space optical communication system.The influence of different types of vibrations should be analyzed when discussing the influence of the satellite vibration on bit error rate.The satellite vibration is firstly simplified to a harmonic motion model.Then square-wave,triangle-wave and backle-wave types of vibrations are respectively analyzed.For sine vibration,the analyzing results show that BER is the function of vibration amplitude and has no relation with vibration frequency when the duration is full period.With vibration amplitude increasing,BER rapidly increases.When the duration is not full period,following increase of time,BER fluctuates and the change of BER is less and less and tendency a constant with amplitude.
Because of the vibration of the satellite,the bit error rate(BER) will be influenced in a space optical communication system.The influence of different types of vibrations should be analyzed when discussing the influence of the satellite vibration on bit error rate.The satellite vibration is firstly simplified to a harmonic motion model.Then square-wave,triangle-wave and backle-wave types of vibrations are respectively analyzed.For sine vibration,the analyzing results show that BER is the function of vibration amplitude and has no relation with vibration frequency when the duration is full period.With vibration amplitude increasing,BER rapidly increases.When the duration is not full period,following increase of time,BER fluctuates and the change of BER is less and less and tendency a constant with amplitude.
2002, 26(1): 9-11,28.
Abstract:
Based on the generalized Huygens-Fresnel diffraction integral and the effect introduced by astigmatism,the transformation properties of super- Gaussian beams passing an astigmatic lens are studied numerically,and some important results are obtained.The beam quality of astigmatic super Gaussian beams is analyzed in terms of power in the bucket,and illustrated with numerical examples.
Based on the generalized Huygens-Fresnel diffraction integral and the effect introduced by astigmatism,the transformation properties of super- Gaussian beams passing an astigmatic lens are studied numerically,and some important results are obtained.The beam quality of astigmatic super Gaussian beams is analyzed in terms of power in the bucket,and illustrated with numerical examples.
Solution of the inverse of high-power multi-pass amplifier with improved successive iteration method
2002, 26(1): 12-14.
Abstract:
The successive iteration method to solve the inverse problem of high-power multi-pass amplifier system is proposed,in which the effects of fabrication imperfection and obscuration of optical components and B integral are considered.The flow chart of calculation codes is shown.Two-pass amplifier system has been taken as a typical example to illustrate the application of the method.The inverse problem of two-pass amplifier has been studied.
The successive iteration method to solve the inverse problem of high-power multi-pass amplifier system is proposed,in which the effects of fabrication imperfection and obscuration of optical components and B integral are considered.The flow chart of calculation codes is shown.Two-pass amplifier system has been taken as a typical example to illustrate the application of the method.The inverse problem of two-pass amplifier has been studied.
2002, 26(1): 15-16,25.
Abstract:
In the paper,the experimental measurement and calculation has been performed on thermal lens,stress birefringence and depolarization in Nd:YAG laser rod.The experimental data are consistent with the calculation results.
In the paper,the experimental measurement and calculation has been performed on thermal lens,stress birefringence and depolarization in Nd:YAG laser rod.The experimental data are consistent with the calculation results.
2002, 26(1): 17-19,22.
Abstract:
Interleukin 1 receptor antagonist(IL-1ra) can interrupt effects of IL-1 in immunity response,infection,inflammation and injury of body.The laser burnt rabbit cornea has been used to study the therapeutical effect of IL-1ra.Through observation of slit-lamp and pathology,determination OD value of cornea and activity of corneal epithelial cell and burnt cornea image analysis,the results indicate that IL-1ra is medicable for laser burnt cornea.
Interleukin 1 receptor antagonist(IL-1ra) can interrupt effects of IL-1 in immunity response,infection,inflammation and injury of body.The laser burnt rabbit cornea has been used to study the therapeutical effect of IL-1ra.Through observation of slit-lamp and pathology,determination OD value of cornea and activity of corneal epithelial cell and burnt cornea image analysis,the results indicate that IL-1ra is medicable for laser burnt cornea.
2002, 26(1): 20-22.
Abstract:
Following the difference of double Gaussian function describing the proximity effects in laser direct writing,the distortion of the mask and its influence on projection lithography pattern quality are simulated.The results show that the area deviation of the mask fabricated by laser writer is about 5% and make the projection lithography quality worse.
Following the difference of double Gaussian function describing the proximity effects in laser direct writing,the distortion of the mask and its influence on projection lithography pattern quality are simulated.The results show that the area deviation of the mask fabricated by laser writer is about 5% and make the projection lithography quality worse.
2002, 26(1): 23-25.
Abstract:
The operating performances of a 50W laser diode arrays have been tested.The output power fluctuation of the laser diode arrays caused by the temperature variation of the cooling water has been measured.The center -wavelength shift of the laser diode arrays caused by the current variation and the temperature variation of the cooling water has been studied.The operating performance is importanat for the design of a diode pumped solid state Nd:YAG laser.
The operating performances of a 50W laser diode arrays have been tested.The output power fluctuation of the laser diode arrays caused by the temperature variation of the cooling water has been measured.The center -wavelength shift of the laser diode arrays caused by the current variation and the temperature variation of the cooling water has been studied.The operating performance is importanat for the design of a diode pumped solid state Nd:YAG laser.
2002, 26(1): 26-28.
Abstract:
Studies have been made on the validity of perturbation approximation when analyzing the rate equations of semiconductor lasers respectively subject to small gain and loss modulations.It is found that for a current or gain modulated diode laser,the neglected second order small quantity in the perturbation method is comparable to the square of the retained first order small quality.For a loss modulation where the threshold carrier density may change,the neglected term may become comparable to the retained first order small quantity.Taking an external cavity laser diode(ECLD) as an example,calculations indicate that the perturbation analysis may become invalid under loss modulation.
Studies have been made on the validity of perturbation approximation when analyzing the rate equations of semiconductor lasers respectively subject to small gain and loss modulations.It is found that for a current or gain modulated diode laser,the neglected second order small quantity in the perturbation method is comparable to the square of the retained first order small quality.For a loss modulation where the threshold carrier density may change,the neglected term may become comparable to the retained first order small quantity.Taking an external cavity laser diode(ECLD) as an example,calculations indicate that the perturbation analysis may become invalid under loss modulation.
2002, 26(1): 29-32.
Abstract:
The basic physics of photon localization in random optical system and its research topics have been described.Some important experiments to observe the phenomena of strong photon localization with ordinary lasers are introduced.Experimental results of photon localization at time domain with ultrashort laser pulses are summarized.It is recommended to enhance the study on generation of tunable mid infrared ultrashort laser pulses in order to stimulate the investigation on the photon localization at mid-infrared wavelength range.
The basic physics of photon localization in random optical system and its research topics have been described.Some important experiments to observe the phenomena of strong photon localization with ordinary lasers are introduced.Experimental results of photon localization at time domain with ultrashort laser pulses are summarized.It is recommended to enhance the study on generation of tunable mid infrared ultrashort laser pulses in order to stimulate the investigation on the photon localization at mid-infrared wavelength range.
2002, 26(1): 33-34.
Abstract:
Based on the derived analytical expression for the output pulse intensity of the input chirped optical pulse transmitting a F-P filter,the output peak power has been studied for different cases.It is found that the peak power changes with the width and the chirp of the input pulse.
Based on the derived analytical expression for the output pulse intensity of the input chirped optical pulse transmitting a F-P filter,the output peak power has been studied for different cases.It is found that the peak power changes with the width and the chirp of the input pulse.
2002, 26(1): 35-37,40.
Abstract:
Based on the 16 phase level binary optical elecment(BOE) designed to convert a given single-mode He-Ne laser beam into a ring-shaped intensity distribution,its shaping effect is numerically simulated for different input beam radii.The simulation results show that the relative mean-square deviation of the shaped amplitude is less than 5% when the difference between the input beam radius and the designed one is within the range of ±50μm.Furthermore,experiment results have been presented for the case that the input beam radius is 1.745mm and the -wavelength for the semiconductor is 660nm.
Based on the 16 phase level binary optical elecment(BOE) designed to convert a given single-mode He-Ne laser beam into a ring-shaped intensity distribution,its shaping effect is numerically simulated for different input beam radii.The simulation results show that the relative mean-square deviation of the shaped amplitude is less than 5% when the difference between the input beam radius and the designed one is within the range of ±50μm.Furthermore,experiment results have been presented for the case that the input beam radius is 1.745mm and the -wavelength for the semiconductor is 660nm.
2002, 26(1): 38-40.
Abstract:
The double exposure fractional Fourier transform hologram (D-EFRTH) is presented and analyzed in the paper.Based on a fabricated D-EFRTH,its performances are analyzed and its special reconstruction condition and appliccations are discusssed.
The double exposure fractional Fourier transform hologram (D-EFRTH) is presented and analyzed in the paper.Based on a fabricated D-EFRTH,its performances are analyzed and its special reconstruction condition and appliccations are discusssed.
2002, 26(1): 41-43.
Abstract:
Some problems present in the process of adjustment for a self-developed capillary-discharge-pumped table-top X-ray laser have discussed in the paper.Under the condition that the capillary charge filled with Ar gas,a significant result has been obtained with output current of 38kA,current pulse rising edge of 40ns.At present,experimental study on Ar filled capillary discharge fluorescence spectra is proceeding on the setup.
Some problems present in the process of adjustment for a self-developed capillary-discharge-pumped table-top X-ray laser have discussed in the paper.Under the condition that the capillary charge filled with Ar gas,a significant result has been obtained with output current of 38kA,current pulse rising edge of 40ns.At present,experimental study on Ar filled capillary discharge fluorescence spectra is proceeding on the setup.
2002, 26(1): 44-46.
Abstract:
After studying the optical modulation characteristics of twisted nematic liquid crystal teveision(LCTV),the edge enhancement of optical image is realized based on optical interference effect and correspondence between gray image and phase modulation.The result is excellent.The system is compact and easy to operate.
After studying the optical modulation characteristics of twisted nematic liquid crystal teveision(LCTV),the edge enhancement of optical image is realized based on optical interference effect and correspondence between gray image and phase modulation.The result is excellent.The system is compact and easy to operate.
2002, 26(1): 47-49.
Abstract:
The performance of PV type InSb detector illuminated by CW CO2 laser with different power density and time duration has been measured so that the damage threshold range of 72W/cm2×(4～5)s is obtained.Based on one-dimension thermal model,thermal increase is theoretically calculated with the detector illuminated by laser.Results show that the detector damage source is the temperature in the proccess of CW laser illumination which gets up to the melt point of InSb so that its p-n junction becomes a resistance.
The performance of PV type InSb detector illuminated by CW CO2 laser with different power density and time duration has been measured so that the damage threshold range of 72W/cm2×(4～5)s is obtained.Based on one-dimension thermal model,thermal increase is theoretically calculated with the detector illuminated by laser.Results show that the detector damage source is the temperature in the proccess of CW laser illumination which gets up to the melt point of InSb so that its p-n junction becomes a resistance.
2002, 26(1): 50-52.
Abstract:
Based on holographic technique,the principle and experimental device for 3D profile measurement are introduced in the papaer.The holographic interference fringe is used instead of projected fringe.Meanwhile,phase shifting technique is used to calculate the phase of the fringe and the wrapped phase distribution of the holographic fringe is produced.Then the unwrapping process will be made by means of the height obtained based on the least square of the projected fringe.Thus,phase measurement can be obtained with higher precision.Finally,the 3D shape data can be produced according to geometric relationship between phase and the object height.
Based on holographic technique,the principle and experimental device for 3D profile measurement are introduced in the papaer.The holographic interference fringe is used instead of projected fringe.Meanwhile,phase shifting technique is used to calculate the phase of the fringe and the wrapped phase distribution of the holographic fringe is produced.Then the unwrapping process will be made by means of the height obtained based on the least square of the projected fringe.Thus,phase measurement can be obtained with higher precision.Finally,the 3D shape data can be produced according to geometric relationship between phase and the object height.
2002, 26(1): 53-54.
Abstract:
Experimental investigation of stimulated Birllouin scattering(SBS) in SF6 gas of 2×106Pa has been made with a broadband KrF laser dispersed by a prism.The results show that SBS reflectivity with dispersive KrF laser used as the pump laser is higher than that with KrF laser directly used as the pump laser.
Experimental investigation of stimulated Birllouin scattering(SBS) in SF6 gas of 2×106Pa has been made with a broadband KrF laser dispersed by a prism.The results show that SBS reflectivity with dispersive KrF laser used as the pump laser is higher than that with KrF laser directly used as the pump laser.
2002, 26(1): 55-57.
Abstract:
The transmittance and optical density have been measured with 1.06μm and 0.53μm laser passing through a sight scope.Biological experiments have done on rabbits and biological evaluation results are presented.
The transmittance and optical density have been measured with 1.06μm and 0.53μm laser passing through a sight scope.Biological experiments have done on rabbits and biological evaluation results are presented.
2002, 26(1): 58-60.
Abstract:
VO2 thin films are prepared under different conditions and irradiated by electron beam with fluence of 1013/cm2～1017/cm2.The phase transition properties and temperature coefficient of resistance are measured with or without electron irradiation.The results show that different preparation conditions and electron irradiation can change the phase transition properties and TCR in VO2 thin films.Other factors that affect the electrical properties and TCR in VO2 thin films have also been discussed.
VO2 thin films are prepared under different conditions and irradiated by electron beam with fluence of 1013/cm2～1017/cm2.The phase transition properties and temperature coefficient of resistance are measured with or without electron irradiation.The results show that different preparation conditions and electron irradiation can change the phase transition properties and TCR in VO2 thin films.Other factors that affect the electrical properties and TCR in VO2 thin films have also been discussed.
2002, 26(1): 61-62,65.
Abstract:
Because quasi-Fermi levels of a laser diode(LD) vary with the carrier density,it is predicted that a hysteresis loop should occur for the current passing LD while a hysteresis loop appears for the power-frequency curve of a tunable external cavity semiconductor.
Because quasi-Fermi levels of a laser diode(LD) vary with the carrier density,it is predicted that a hysteresis loop should occur for the current passing LD while a hysteresis loop appears for the power-frequency curve of a tunable external cavity semiconductor.
2002, 26(1): 63-65.
Abstract:
The measurement principle and the adjustment of type 2523 laser tensional vibration meter is introducced.The error sources have been found and hence the measures to reduce the error are presented.
The measurement principle and the adjustment of type 2523 laser tensional vibration meter is introducced.The error sources have been found and hence the measures to reduce the error are presented.
2002, 26(1): 66-67,70.
Abstract:
The propagation of the Bessel-modulated Gaussian beams with quadratic radial dependence (QBG beams) has been studied,where the passage of QBG beams through a first-order paraxial ABCD optical system has been expressed in a closed-form.As an example,the propagation through a thin lens has been discussed.Numerical calculation examples have been presented to illustrate the propagation properties of QBG beams.
The propagation of the Bessel-modulated Gaussian beams with quadratic radial dependence (QBG beams) has been studied,where the passage of QBG beams through a first-order paraxial ABCD optical system has been expressed in a closed-form.As an example,the propagation through a thin lens has been discussed.Numerical calculation examples have been presented to illustrate the propagation properties of QBG beams.
2002, 26(1): 68-70.
Abstract:
Laser hardening process and machining process parameters for tablet punch pin have been studied.A 2kW CO2 laser is used to harden the punch pin for a pharmaceutical factory.Through laser hardening,petty martensite has obtained with a depth of 0.7mm.Results show that the working surface of the punch pin hardened by laser has higher hardness and strength,abrasive resistance,impact resistance and longer life.This paper introduces the laser hardening process to improve material organization,reduce stress on variable sections,prevent crack produced in the process of manufacture and improve the combined mechanical performances of the punch pin.
Laser hardening process and machining process parameters for tablet punch pin have been studied.A 2kW CO2 laser is used to harden the punch pin for a pharmaceutical factory.Through laser hardening,petty martensite has obtained with a depth of 0.7mm.Results show that the working surface of the punch pin hardened by laser has higher hardness and strength,abrasive resistance,impact resistance and longer life.This paper introduces the laser hardening process to improve material organization,reduce stress on variable sections,prevent crack produced in the process of manufacture and improve the combined mechanical performances of the punch pin.
2002, 26(1): 71-74,52.
Abstract:
A horizontal beam deflector with a rotating polycylinder mirror used for the situation of high scan frequuency is newly designed.The material and processing technology of the cylinder body are brought forward.The optical character and the scan result of the rotating polycylinder mirror are studied.The dynamic character of the rotating polyclinder-mirror is studied too.The lens to correct the scan light nonlinear deflection by the rotating mirror is studied.As the horizontal beam deflector,the rotating polycylinder-mirror can simplify the structure and decrease the cost of system.The static and dynamic balance is easy to be insured because of the lower rotating speed of polycylinder-mirror,and also resulted in a high rotating precision.The light deflected by the rotating mirror can be corrected by correcting lens,which inccreases the property of system.
A horizontal beam deflector with a rotating polycylinder mirror used for the situation of high scan frequuency is newly designed.The material and processing technology of the cylinder body are brought forward.The optical character and the scan result of the rotating polycylinder mirror are studied.The dynamic character of the rotating polyclinder-mirror is studied too.The lens to correct the scan light nonlinear deflection by the rotating mirror is studied.As the horizontal beam deflector,the rotating polycylinder-mirror can simplify the structure and decrease the cost of system.The static and dynamic balance is easy to be insured because of the lower rotating speed of polycylinder-mirror,and also resulted in a high rotating precision.The light deflected by the rotating mirror can be corrected by correcting lens,which inccreases the property of system.
2002, 26(1): 75-78.
Abstract:
Based on triangular prism's functions of beam expansion and angle magnification,the influence of adjustable beam splitting prism on divergence angle and cross section at different incident angles has been studied.The results are useful to the application of this type of polarizer.
Based on triangular prism's functions of beam expansion and angle magnification,the influence of adjustable beam splitting prism on divergence angle and cross section at different incident angles has been studied.The results are useful to the application of this type of polarizer.
2002, 26(1): 79-80.
Abstract:
The effect of CO2 laser treatment on CA is introduced and the relapse cause is analyzed in the paper.Based on 192 treatments on 146 CA patients,a conclusion has been made that CO2 laser can cure CA,however,the relapse rate will decrease if the a CA patient can be treated with disease cause,immune enhance dray and/or Chinese herbal medicine.
The effect of CO2 laser treatment on CA is introduced and the relapse cause is analyzed in the paper.Based on 192 treatments on 146 CA patients,a conclusion has been made that CO2 laser can cure CA,however,the relapse rate will decrease if the a CA patient can be treated with disease cause,immune enhance dray and/or Chinese herbal medicine.
