Journals >Chinese Journal of Lasers
Contents
1997
Volume: 24 Issue 9
21 Article(s)
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Research Article
Calculation of the Temperature Distribution inside Semiconductor Films Irradiated by a Pulsed Laser
[in Chinese], [in Chinese], and [in Chinese]
Temperature distributions induced by laser pulses in an absorptive semiconductor film deposited on a non absorptive substrate have been calculated. For cases of a Si:H film and a Si:H/ a SiN x: H multi quantum well structure on the quartz substrates irradiated by the KrF pulsed excimer laser, we analyzed the effecTemperature distributions induced by laser pulses in an absorptive semiconductor film deposited on a non absorptive substrate have been calculated. For cases of a Si:H film and a Si:H/ a SiN x: H multi quantum well structure on the quartz substrates irradiated by the KrF pulsed excimer laser, we analyzed the effect of film thickness, laser energy density and the ratio of sublayers′ thicknesses of a Si:H/ a SiN x: H MQW structure on the temperature distribution and crystallization of a-Si:H and a-Si:H/a-SiNx:H MQW structure..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 803 (1997)
Research of Torsional Vibration Measurement of High speed Rotating Mechanical Devices
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, the characteristics of torsional vibration of high speed rotating mechanical devices as well as requests for the measuring system is discussed. As far as these requests are concered, a new laser Doppler torsional vibration measuring method is given.In this paper, the characteristics of torsional vibration of high speed rotating mechanical devices as well as requests for the measuring system is discussed. As far as these requests are concered, a new laser Doppler torsional vibration measuring method is given..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 809 (1997)
The Measure提出了一种基于脉冲数字散斑干涉(DSPI)系统的心动位移测量技术。该技术利用激光照射体表产生的动态生物散斑相关条纹图提取并记录心动周期时间历程中瞬态空-时位移场分布,进而通过条纹自动分析技术获得高精度重建的光学心动图。ment of Cardiac Displacement Using DSPI
[in Chinese], and [in Chinese]
We present a DSPI based technique for measuring cardiac displacement. Body surface illuminated by a coherent laser will diffuse light and generate dynamic speckle field in the space. By using correlation fringe pattern produced from double exposure speckle patterns we can record temporal spatial displacement distributiWe present a DSPI based technique for measuring cardiac displacement. Body surface illuminated by a coherent laser will diffuse light and generate dynamic speckle field in the space. By using correlation fringe pattern produced from double exposure speckle patterns we can record temporal spatial displacement distribution in the cardiac cycle with double pulsed digital speckle pattern interferometry. Furthermore, it can also be possible to obtain reconstructed optical cardiogram with high accuracy throug the technique of automatic fringe analysis..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 814 (1997)
Research of Detection of Solid Surface Laser Ultrasonic Pulses Using a Laser Heterodyne Interferometric Method
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This paper describes the measuring principle and an experimental study of laser ultrasonic pulses by the laser heterodyne interferometric method. A method of increasing the intensity of the detected signal is developed.This paper describes the measuring principle and an experimental study of laser ultrasonic pulses by the laser heterodyne interferometric method. A method of increasing the intensity of the detected signal is developed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 819 (1997)
Life Extension of Thyratron in Excimer Laser Generator with Use of Magnetic Assist
The anode erosion in a thyratron during operation is analyzed. The design of magnetic assist to extend thyratron lifetime is presented. Addition of the magnetic assistor reduces anode dissipation and mitigates reverse current, hence reducing thyration cooling requirement and anode erosion. The experimental results are The anode erosion in a thyratron during operation is analyzed. The design of magnetic assist to extend thyratron lifetime is presented. Addition of the magnetic assistor reduces anode dissipation and mitigates reverse current, hence reducing thyration cooling requirement and anode erosion. The experimental results are presented..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 823 (1997)
Holography and Information Processing
Real time Nonlinear Joint Transform Correlator
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Utilizing a liquid crystal light valve (LCLV), which is produced in China and is made to work in high contrast state, to realize nonlinear joint transform correlation is proposed in this paper. The nonlinear modulation principle of the LCLV has been explained by analyzing the light propagation property in the liquid crUtilizing a liquid crystal light valve (LCLV), which is produced in China and is made to work in high contrast state, to realize nonlinear joint transform correlation is proposed in this paper. The nonlinear modulation principle of the LCLV has been explained by analyzing the light propagation property in the liquid crystal box. The idea of using high contrast LCLV to realize nonlinear joint transform correlation is confirmed by comparing the computer simulation results with the optical experimental results with the optical experimental results..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 837 (1997)
Laser Manufacturing
High power Laser Welding Monitoring with Dual waveband Signals
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Dual waveband signals in high power laser welding were recorded and analyzed, especially, the law between the signals magnitude and the defocusing was discussed.Dual waveband signals in high power laser welding were recorded and analyzed, especially, the law between the signals magnitude and the defocusing was discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 842 (1997)
Research on Constitution of the cw Laser Glazed Fe C Si B Eutectic Alloy Layer
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Bright layers covering 80% of the melt area have been achieved by laser glazing on Fe C Si B eutectic matrix prealloyed by laser on cast iron substrates. The bright layers appear only when the epitaxial growth from the Fe C Si B eutectic matrix stops abruptly during solidification. It is proved by TEM and HR SEM analysBright layers covering 80% of the melt area have been achieved by laser glazing on Fe C Si B eutectic matrix prealloyed by laser on cast iron substrates. The bright layers appear only when the epitaxial growth from the Fe C Si B eutectic matrix stops abruptly during solidification. It is proved by TEM and HR SEM analyses that the bright layer consists of three sublayers: the upper sublayer is homogeneous nanocrystalline, the middle sublayer is metallic glass, and the lower sublayer is heterogeneous nanocrystalline..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 847 (1997)
Deposition of a High Current Density YBCO Thick Film on NiCr Alloy Substrate Tape by Pulsed Laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The buffered layer Y-ZrO 2 (YSZ) was deposited on the flexible metallic NiCr substrate tape of 6.0 cm in length by a KrF laser and ion beam assisted deposition (IBAD), and then YBCO superconducting thick films were deposited on the YSZ/NiCr in order to obtain a high current density YBCO superconducting tape for power aThe buffered layer Y-ZrO 2 (YSZ) was deposited on the flexible metallic NiCr substrate tape of 6.0 cm in length by a KrF laser and ion beam assisted deposition (IBAD), and then YBCO superconducting thick films were deposited on the YSZ/NiCr in order to obtain a high current density YBCO superconducting tape for power applications. The thickness of 1.5 μm and 0.13 μm is for the YBCO and the YSZ, respectively. The critical current density of YBCO/YSZ/NiCr is 8.75×10 4 A/cm 2 at 77 K, 0 Tesla, the cirtical temperature is 88.6 K..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 853 (1997)
Solid Model Formation of a Photo polymer under Copper Vapor Laser Irradiation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, a photopolymer with the peak absorption wavelength of 252 nm is reported. And after the photopolymer being irradiated about 30 minutes at an average output laser power density of 1 mW/mm 2, a solid model of the size of 12×2.5×5 (mm) was obtained.In this paper, a photopolymer with the peak absorption wavelength of 252 nm is reported. And after the photopolymer being irradiated about 30 minutes at an average output laser power density of 1 mW/mm 2, a solid model of the size of 12×2.5×5 (mm) was obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 857 (1997)
The Counting of Board Articles by Means of Laser Scan
[in Chinese], and [in Chinese]
On the basis of the principle of laser scan, the counting method for different board articles which are piled in layers, irregular, and with coloured or black to white surfaces, is studied. By traditional methods the counting of these articles is difficult to do or have limited precision and counting rate. The countingOn the basis of the principle of laser scan, the counting method for different board articles which are piled in layers, irregular, and with coloured or black to white surfaces, is studied. By traditional methods the counting of these articles is difficult to do or have limited precision and counting rate. The counting principle, the determination of the positions of the incident laser beam and of the installation of the sensors, the measuring system, and the experimental results are presented..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 860 (1997)
Laser Physics
Influence of Spontaneous Emission in Injection Locked Copper Vapor Laser
[in Chinese]
The competition between the injected laser and the amplified spontaneous emission in an unstable resonator is studied numerically with a dynamic model of injection locked copper vapor laser, and the effectiveness of injection locking is analysized with injected power. At last the problem about how to increase the effecThe competition between the injected laser and the amplified spontaneous emission in an unstable resonator is studied numerically with a dynamic model of injection locked copper vapor laser, and the effectiveness of injection locking is analysized with injected power. At last the problem about how to increase the effectiveness of injection locking is discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 769 (1997)
Electron Energy Deposition for KrF Laser with Bidirectional Four e beams Pump
[in Chinese], [in Chinese], and [in Chinese]
The spatial profile of the energy deposition for the main amplifier (H1M) of a KrF laser MOPA system is presented by meams of 3D Monte Carlo method. The effects of Hibachi structure and main foils are considered. For 0.5 MeV electron, the energy deposition distributions of pumping direction are almost uniform. In the lThe spatial profile of the energy deposition for the main amplifier (H1M) of a KrF laser MOPA system is presented by meams of 3D Monte Carlo method. The effects of Hibachi structure and main foils are considered. For 0.5 MeV electron, the energy deposition distributions of pumping direction are almost uniform. In the lasing direction (axial), because of a 14 cm unpumped area between two e beam windows the spatial profile of energy deposition takes the shape of a saddle. The peak valley ratio is 2～3. In addition, the relations of the total deposition energy and the energy deposition efficiency with the e-beam energy are given. The total deposition energy and the energy deposition efficiency reach the maximum when the e-beam energy is equal to 0.5 MeV and 0.31 MeV, respectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 774 (1997)
Efficient Femtosecond Visible Collinear Optical Parametric Generator and Amplifier with Tilted Pulse Pumping
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Compensating for the group velocity mismatch in optical parametric interaction with tilted pumping pulse fronts, an efficient femtosecond collinear type Ⅰ phase matched β barium borate optical parametric generator and amplifier pumped by a tilted second harmonic pulses of the Ti sapphire regenerative amplifier is demoCompensating for the group velocity mismatch in optical parametric interaction with tilted pumping pulse fronts, an efficient femtosecond collinear type Ⅰ phase matched β barium borate optical parametric generator and amplifier pumped by a tilted second harmonic pulses of the Ti sapphire regenerative amplifier is demonstrated. The signal and idler outputs are tunable from 470 nm to 2.7 μm having pulse widths in the range of 100 to 170 fs at 1 kHz repetition rate. A maximum output energy of 6.5 μJ/pulse and a total conversion efficiency of more than 15% are achieved..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 779 (1997)
On Tunable, Narrow Spectral Width Operation of a KrF Laser and Injected Amplification
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
We obtain a spectral width less than 0.1 nm and a tunability about 1 nm by adding a grating, a beam expander, shutters and a combining lens in the oscillator of a discharge pumped ArF laser oscillator amplifier system. The output power is injected into the amplifier that produces an average energy of 30 mJ/pulse, and tWe obtain a spectral width less than 0.1 nm and a tunability about 1 nm by adding a grating, a beam expander, shutters and a combining lens in the oscillator of a discharge pumped ArF laser oscillator amplifier system. The output power is injected into the amplifier that produces an average energy of 30 mJ/pulse, and the tunable, narrow spectral, and very low beam divergence laser output. The efficiency is increased about 50 percent after injection. A peak output of more than 50 mJ/pulse is achieved. The O2 absorption of the ArF laser is also measured..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 784 (1997)
The Experimental Investigation on Impedance Matching and Modulation of RF excited CO>sub>2Laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The principle and experiment of an impedance maching network between the RF source and the laser head, which is neccessary for RF discharge, is described. According to the parameters of a built up 1 kW RF exciting axial flow CO 2 laser, the results of calculation of RF gas discharge impedance and the on moving matchingThe principle and experiment of an impedance maching network between the RF source and the laser head, which is neccessary for RF discharge, is described. According to the parameters of a built up 1 kW RF exciting axial flow CO 2 laser, the results of calculation of RF gas discharge impedance and the on moving matching are presented..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 787 (1997)
A Self pulsed Intercavity Pumped Er 3+ doped Fiber Laserc
[in Chinese], [in Chinese], and [in Chinese]
A novel self pulsed Er 3+ doped fiber laser pumped internally is presented in this paper. Stable T periodic and 2T periodic pulses have been achieved under the low pump power with the CW pumping mode. The experimental results indicate that the main mechanism of the nonlinear dynamics phenomena results from the transienA novel self pulsed Er 3+ doped fiber laser pumped internally is presented in this paper. Stable T periodic and 2T periodic pulses have been achieved under the low pump power with the CW pumping mode. The experimental results indicate that the main mechanism of the nonlinear dynamics phenomena results from the transient loss difference between the two orthogonal states of polarization..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 793 (1997)
Experimental Study of Two stage Erbium Doped Fiber Amplifiers Pumped by 980 nm and 1480 nm LD
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on a two stage fiber, Erbium doped fiber amplifiers (EDFAs) pumped by 980 nm and 1480 nm laser diodes (LD) are investigated. Experimental comparisons of gain, noise figure and output power between the intermediate isolator configuration and the loop coupling configuration are discussed. A small signal gain of 42.Based on a two stage fiber, Erbium doped fiber amplifiers (EDFAs) pumped by 980 nm and 1480 nm laser diodes (LD) are investigated. Experimental comparisons of gain, noise figure and output power between the intermediate isolator configuration and the loop coupling configuration are discussed. A small signal gain of 42.8 dB of EDFA has been obtained for the loop coupling configuration. The minimum noise figure and maximum output power at wavelength of 1553.5 nm are 4.4 dB and 15.2 dBm, respectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 797 (1997)
[in Chinese]
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 802 (1997)
The Study of the Triplet State of C60by a Time resolved Thermal Lensing Technique
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The quantum yield of triplet formation (φISC) and the triplet lifetime (τT) of C 60 , as well as the quantum yield of singlet oxygen formation (φΔ) by the quenching of the triplet state of C60 and the singlet lifetime (τ0) of oxygen are measured by a time resolved thermal lensing technique. Both φISC and φΔ are nearly The quantum yield of triplet formation (φISC) and the triplet lifetime (τT) of C 60 , as well as the quantum yield of singlet oxygen formation (φΔ) by the quenching of the triplet state of C60 and the singlet lifetime (τ0) of oxygen are measured by a time resolved thermal lensing technique. Both φISC and φΔ are nearly unity and the lifetimes of both the triplet C60 and the singlet oxygen are in the range of 8￣60 μs and 20 μs respectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 828 (1997)
Generation of Ultraviolet Radiation with Parametric Four wave Mixing in Sodium Vapor
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The 330 nm PFWM coherent radiation near the 4D two photon resonance were recorded and analysed in sodium vapor. The variation of the intensity is described and the optimum condition is found.The 330 nm PFWM coherent radiation near the 4D two photon resonance were recorded and analysed in sodium vapor. The variation of the intensity is described and the optimum condition is found..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 9, 833 (1997)
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