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ISSN1001-3806 CN51-1125/TN Map

1997 Vol. 21, No. 2

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Absolute distance interferometry using multiwavelength lasers:theories and progress review
Deng Luogen
1997, 21(2): 71-74.
Abstract:
Absolute distance interferometry (ADI) for large length measurements has been studied for several decades.In this period,many breakthroughs in ADI art have been achieved.Recent years,this technique has came to maturity in the subject of long distance measurement.Starting from the point of the detailed description of ADI principles,this paper reviews the development history of ADI,analyses the current state and future trends of ADI emphasizes the application of the multiwavelength infrared lasers in this subject.
Evaluation to some making methods of embossing holographic master
Gong Ailing, Zhang Wembi, Zhong Liyun, Yang Qimin, Xiong Bingheng
1997, 21(2): 74-76.
Abstract:
This paper compared several methods of making the photoresist embossing holographic master and gave out the evaluation.The one-step imaging process provide the functions of the better effect and simple process,but the method needs huge investment.For one-step direct method,it is essential to have a two dimension pattern plate with high resolution,high contrast and low noise.Otherwise than one-step imaging process,the one-step direct method needn't high quality equipments,so the investmen is lower.The one-step projection method can not provide better effect and is seriously restricted by the operating condition,so the method is used only when others can not be used.Owing to the aberration of master and lower utilization ratio of light energy,the two-step method is used only as an auxi liary means of one-step direct method.
Direct coupling of high-power LD to the multi mode optical fiber
Jiao Mingxing, Zhang Shulian, Liang Jinwen, Wei Chaojiong, Zha Kaide
1997, 21(2): 77-80.
Abstract:
High power LD is directly coupled to the multi-mode optical fiber whose end is uptapered by polishing.Some main factors affecting the coupling efficiency are analysed.Proposed is a novel method of carrying out the direct coupling,with the help of the tool-maker's microscope, a coupling efficiency of higher than 50.8 percent is obtained.
Thermal coupling coefficient of metal material to CW IR laser
Chen Jinbao, Zhang Zhenwen, Zhao Yijun
1997, 21(2): 81-83.
Abstract:
Using a integrating sphere designed by ourselves,we measured the thermal coupling coefficients of several kinds of LY12 Al alloy targets having different surface situations to CW CO2 laser beam(the power is about 40W).The experiment results show the fact that the test values are bigger than the calculation values by the classical theory.This paper presented the analysis to the fact,and points out the surface defects will much increase the thermal coupling coefficient.
Influence of surface scattering of complicated object on holographic interferogram visibility and its process technique
Jiang Lingzhen, Zhan Decheng, Li Chengjiang
1997, 21(2): 83-86.
Abstract:
In general,the surface scattering will influence on the visibility of the holographic interferogram.Some times,the influence is so serious that it is almost not possible to recognize the object displayed in interferogram.As well as a complicated object,the visibility of the holographic interferograms of the printed circuit board have be getting lower by the scattering of the surface and solder joints.This paper presented a fringe detection method in a slide windows to reconstruct the interferogram fringe.With the method,it is possible correctly to decide the location of the solder joints.
Properties of three processes of laser surface treatment of aluminium alloy
Zhao Wenzhen
1997, 21(2): 87-91.
Abstract:
Surface remelting,surface alloying and surface cladding are 3 essential processes in the surface modification of aluminium alloy by laser.They are distinctive,but there are some relations each other too.Through testing their microstructures and hardening effects are investigated and contrasted.The study can give guidance for the research and application of surface laser strengthening processes of aluminium alloy.
Magnetic-spiker-sustainer excitation technology and uses in excimer laser
Zhou Weidong, Yu Yinshan
1997, 21(2): 92-95.
Abstract:
Based on the analysis of operating principles of magnetic-spiker-sustainer excitation used in excimer laser,this paper points out the technique is suitable to provide the laser pulses with the high efficiency,high average power and long duration.Experiment results show that the using the technique can generate the 170ns KrF laser pulses and 1μm XeCl laser pulses.
Investigation of dispersion compensation in self mode lockd Ti:Al2O3 lasers
Huang Feiran, Wei Zhiyi, Yang Jie, Yu Zhenxin
1997, 21(2): 96-100.
Abstract:
The dispersion compensation systems with a pair of double prisms or a group of four prisms used in self mode-locked Ti:2O3 lasers are theoretically studied in detail.The accurate expressions of second order and third order dispersion.The compensation results provided by the systems consisting of different optical materials are experimentally investigated.
Investigation of Cr4+:MSO laser with high output energy
Song Dingxi, Wu Youwu, Yang Yong, Zhao Xinan
1997, 21(2): 101-103.
Abstract:
In this paper,experimental results of longitudinally-pumped Cr4+:Mg2SiO4 laser are reported.An output of 135mJ have been obtained by using 1.064μm Nd:YAG pulsed laser pump at room temperature.
A practical auto tuning Ti-saphire laser
Wu Lusheng, Yang Chunling, Zhu Guixia, Wang Aihua, Ying Shaotang
1997, 21(2): 104-106.
Abstract:
In this paper,the design of an auto-tuning Ti-saphire laser is described.The pumping source is a double frequency Nd:YAG laser,the maximum output energy of 60mJ per pulse with 37.5% conversion efficiency has been obtained at the repetition rate of 10Hz.
Visualization of internal structure of fuel spray using laser computed tomography technique(1)——A study of image reconstruction algorithms for fuel spray
Wang Dezhong, Huang Zhen, Chen Laigao Zhang Lianfang, Tong Chengjiao, Zhuang Tiange
1997, 21(2): 106-108.
Abstract:
According to the characteristics of fuel spray,CBP(Convolution back projection),ART (Algebraic reconstruction technique) and SIRT (Simultaneous iterative reconstruction technique) were studied on the image reconstruction of fuel spray.The reconstruction results of the phantom using P540 digital image processing system showed that when there is noise in the projection data,the best image was reconstructed by SIRT whose calculation time was longest,the worst image was reconstructed by CBP whose calculation time was shortest,and ART is between them.
Power tuning for 632.8nm wavelength He-Ne lasers with various frequency spacing by mode split
Han Yanmei, Zhang Shulian, Li Kelan
1997, 21(2): 111-114.
Abstract:
The laser longitudinal mode-split technology provides a powerful tool to study the power tuning property for a laser with various frequency spacing form a few tens of megahertz to half of the longitudinal mode spacing.A serious of experiments have been done.The experimental results show that the power varying trend of o-light and e-light are opposite to each other,no matter what kind of Ne(Ne20 or the mixture of Ne20 and Ne22) is used and how much the mode split is.
Energy analysis about laser wavelength measurement in real time
Lu Hong, Jiang Lingzhen, Geng Wanzhen, Hong Jing
1997, 21(2): 115-119.
Abstract:
The paper analyzed the energy and signal noise ratio (SNR) resulted from the measuring of laser wavelength with a grating.For the measurement of laser wavelength,it is needed to have proper laser energy and SNR.This paper presented the experimental data and taken photographs,and discussed the experimental results from the view point of the energy measurement.
Dynamic measurement of axial and radial jitter of wheel rim by laser
Li Chengzhi, Li Anran
1997, 21(2): 119-121.
Abstract:
By means of optical and CCD image processing technique,a system for detection of the axial and radial jitter of wheel rim is introduced in this paper.With the system,the image of the wheel and the pattern shaded by the wheel are imaged on CCD sensor.According to the variations of the image and the shaded pattern,the axial and radial jitter can be calculated out.This paper gives out the main constructure of the detection system.
Laser techniques of measuring particles size and their size distribution
Yang Ye, Zhang Zhenxi, Jiang Dazong
1997, 21(2): 122-127.
Abstract:
According to the characteristics of fuel spray,CBP (Convolution backprojection),ART (Algebraic reconstruction technique) and SIRT (Simultaneous iterative reconstruction technique),which are used to realize the visualization of the internal structure of fuel spray,are studied in this paper.The reconstruction results with a P540 digital image processing system show that when the noise exists in the projection data,the SIRT provided the best image reconstruction taking the longest calculation time,the worst image reconstruction is obtained by CBP taking the shortest calculation time,and ART is in the middle.
A new optoelectronic detector
Feng Gonghe, Zhou Maohua
1997, 21(2): 128-129.
Abstract:
This artical introduces the new optoelectronic instrument for detection.It utilizes the Fourier transform of laser beam to extract defect data from workpiece,and then curries out optical information processing under microcomputer control.Automatic detect and classificatin of precision parts are implemented.The instrument had been accredited.