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ISSN1001-3806 CN51-1125/TN Map

2002 Vol. 26, No. 2

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Effect of EM field on the plasma control during CO2 laser beam welding
Bao Gang, Wang Cheng, Peng Yun, Chen Wuzu, Tian Zhiling
2002, 26(2): 81-83,93.
Abstract:
During high power CO2 laser beam welding,the plasma above the keyhole will influence the absorption ratio of the laser energy absorbed by the workpiece.In the paper,the feasibility to use assisting electric and magnetic(EM) field as a measure for pla...
Study on the reflected wavelength shift based on sensing elements of in-fiber Bragg gratings
Xie Fang, Zhang Shulian, Li Yan, Liang Jinwen
2002, 26(2): 84-85,96.
Abstract:
A new method is presented to detect the wavelength shift on in fiber Bragg gratings.The system employs a series of in fiber Bragg gratings,having the same parameters as the sensing in fiber Bragg gratings,as filter elements.Furthermore,the system tra...
A numerical simulation for temperature and thermal stress distribution in Nd:YAG amplifiers
Li Minghai, Liu Aiguo, Song Yaozu
2002, 26(2): 86-89.
Abstract:
A 3D transient thermal model with inhomogeneous heat generation is presented to predicate the thermal response in high power/pulse face pumped slab amplifiers.Based on finite element(FE) analysis,the temperature and thermal stress distribution in Nd:...
Measures to improve the accuracy of a real-time temperature measurement system
Shi Deheng, Guo Feng, Liu Yufang, Chen Yuke
2002, 26(2): 90-93.
Abstract:
A real time temperature measurement system with InGaAs/I is introduced at first.Then measures to improve the accuracy are discussed.The first is to select the detector,optimize modulation disk and amplify the signal with selective frequency.The secon...
Micropatterns on polymers etched by excimer lasers
Zhang Lin, Lou Qihong, Wei Yunrong, Dong Jingxing, Li Tiejun, Hang Feng
2002, 26(2): 94-96.
Abstract:
In the paper,the experiment with UV excimer laser etching PI for micropatterns is described in detail.With this method,micropatterns with micron scale line width and sub micron depth have been successfully fabricated on PI.
Dislocation and branch point in optical front——I structure theory
Zhang Yixin, Zhu Tuo, Xu Zhenyuan, Gong Zhiben
2002, 26(2): 97-101.
Abstract:
The recent developments on phase dislocation and branch point in optics are reviewed.It includes the conception,law and study method of wave front dislocation in scalar waves scattered by rough surface and propagate through random media and phenomena...
Numerical simulation for the process of 3D transient convection and heat transfer in the molten pool
Zeng Dawen, Xie Changsheng
2002, 26(2): 102-105.
Abstract:
A 3D model for fluid flow and heat transfer process has been developed to predict the transient distribution of temperature and velocity of a thick solid irradiated by a moving laser.The governing equations are solved by means of a finite difference ...
Effect of the fiber grating length on its peak reflectivity
Xia Guangqiong, Wu Zhengmao, Chen Jianguo
2002, 26(2): 106-107.
Abstract:
Based on the coupled mode theory,the effect of the fiber grating length on its peak reflectivity has been studied for a uniform grating and a DC apodized Gaussian grating.The obtained results are important for a fiber grating external cavity semicond...
Beam quality characterization of super-Gaussian beams passing through a spherically aberrated lens with an annular rectangular apertur
Qing Yusan, Lü Baida
2002, 26(2): 108-110113.
Abstract:
In the paper,the power in the bucket(PIB), β and η parameters are chosen as criteria to characterize the laser beam quality in the far field,then the beam quality of super Gaussian beams passing through a spherically aberrated lens with an annular re...
Experimental study on long period fiber grating applied in two channel wavelength division demultiplexer
He Wanxun, Shi Wenkang
2002, 26(2): 111-113.
Abstract:
A long period fiber grating(LPFG) is a wavelength seletive filter developed in recent years.According to its behavior of wavelength dependent loss,a LPFG is used as wavelength division demultiplexer for 1310nm/1550nm wavelength division multiplexing(...
Multiple-axis pointing control in intersatellite optical communication
Yu Siyuan, Gao Huide, Wang Lisong, Dong Yunhua, Ma Zuguang
2002, 26(2): 114-116.
Abstract:
A proposal is introduced in the paper that the control method of multiple axis pointing can be used to improve the tracking and pointing system in intersatellite optical communication.The models of coarse pointing and fine pointing are set up,and the...
Properties of flattened Gaussian beam in directional prism cavity
Wang Xiaobing, Sun Bin, Cheng Yong, Wang Guchang, Zeng Wenfeng, Wang Dayong
2002, 26(2): 117-119122.
Abstract:
A coherent flattened Gaussian beam has been obtained in the XeCl excimer laser with directional prism.The beam is well distributed in the near field and highly focused in the far field.Immunity to misalignment of excimer laser increases.
Study on laser blood therapy with laser diode radiating the subcutaneous vein at the back of the hand
Luo Xiaosen, Ni Xiaowu, Lu Jian, He Anzhi, Dou Zhongxin, Li Lugang, Yan Yulan, Duan Ping, Liu Jiangang
2002, 26(2): 119-122.
Abstract:
A new laser blood therapy with a laser diode(LD) put close to the skin and radiating the subcutaneous vein is introduced.The subcutaneous vein at the back of the hand is suggested as the target of laser irradiation.The experimental foundation is expl...
Material system of laser cladding ceramic and its composite coatings
Chen Chuanzhong, Wang Diangang, Zhang Liang, Lei Tingquan
2002, 26(2): 123-125128.
Abstract:
The development of laser cladding ceramic and its composite coatings in home and aboard is analyzed.The material system,properties and application prospect of laser clad corrosion resistant,wear resistant,oxidation resistant coatings are reviewed.
Repetitive, Raman shifted, (Nd, Ce):YAG laser with twin-wavelength outputs
Wang Yong, Han Kai, Han Hong, Li Tong, Shao Huaizong
2002, 26(2): 126-128.
Abstract:
Some key techniques of Raman shifted laser with high repetitive frequency and twin wavelength outputs have been studied experimentally.Operating at 15Hz,output laser energy of more than 20mJ with twin wavelengths of 1.54μm and 1.06μm has achieved.
Computation of atom parameters of Ni-like Kr based on OFI
Xia Yuanqin, Lu Xingfa, Chen Deying, Wu Xiaoyan, Wang Qi
2002, 26(2): 129-131137.
Abstract:
Based on Cowan program,atom parameters have been computed.Cowan program,based on Maxwell has been extended to be applicable for any electron distribution with the help of an additional program written by the authors.The computed parameters comprise t...
Beam quality of Gaussian beams passing through a spherically aberrated annular lens
Ji Xiaoling, Lü Baida
2002, 26(2): 132-134.
Abstract:
With power in the bucket(PIB) and β parameter to characterize beam quality,the effect of some parameters,such as spherical aberration coefficient C 4 and obscure ratio ε,on the beam quality of Gaussian beams is analyzed.It is worthwhile to note that ...
Gas control in a fast-flow axial CO2 laser
Xie Qiong, Li Shimin, Xu Zhene, Zhou Xinjun
2002, 26(2): 135-137.
Abstract:
The fast flow axial CO2 laser is usually used for laser cutting because of its good laser beam quality.To ensure the stability of the output laser power,the working gas should be stabilized at an optimal pressure.Based on exact study on the working t...
Intelligent control applied in the servo system based on pattern recognition
Zhang Jianli, Feng Rupeng
2002, 26(2): 138-140.
Abstract:
Speed,accuracy and stability are often required in the response of a system,but they are hardly obtained using traditional methods,such as PID.In the paper,an intelligent control method based on pattern recognition is presented,which can achieve bett...
Study on back-reflected laser from an infrared system
Zhang Dayong, Liu Changling, Yuan Yonghua
2002, 26(2): 141-143.
Abstract:
The characteristics of back reflected laser from an infrared system are investigated in theory and through experiment.The mechanism of back reflection,reflected laser signal characteristics,direction of reflected laser and the application of the refl...
Cr4+:YAG Q-switched SBS laser
Liu Danping, Feng Guoying, Ou Qunfei, Li Cunzhi, Zhong Ming, Sun Nianchun
2002, 26(2): 144-146.
Abstract:
A Cr4+:YAG Q-switched SBS laser has been studied experimentally and calculated numerically.The results prove that appropriate combination of two passive Q switched can enhance the laser's stability.
Design method of echo probability in a laser tracking system
Zheng Yongchao, Zhan Rongke, Yang Zhiqing
2002, 26(2): 147-149.
Abstract:
In the paper,the principle of laser tracking is described and the important factors affecting the echo probability of a laser tracking system are analyzed.The basic method and rules to choose circuit loop parameters to ensure a certain echo probabili...
OPO-CARS thermometry and influence of slit function on precision
Zheng Yongmei, Shen Xuanguo, Gu Feng
2002, 26(2): 150-152.
Abstract:
A new broadband coherent anti Stoke Raman spectral(CARS) thermoscope,consisting of a frequency double Nd:YAG laser and an optical parametric oscillator(OPO) instead of the dye laser,is introduced.In order to increase the precision of CARS temperature...
Waist width of Hermite-cosh-Gaussian beams
Wang Li, Wang Xiqing, Lü Baida
2002, 26(2): 153-155149.
Abstract:
Based on the second-order moment method,the closed form expression of the waist width of Hermite-cosh-Gaussian beams is derived.For example,the closed form expressions of the waist width for Hermite-cosine-Gaussian,cosh-Gaussian,cosine-Gaussian and H...
Transient criterion of non-Fourier heat conduction law
Yu Ning, Pan Jiansheng, Gu Jianfeng, Hu Mingjuan
2002, 26(2): 156-158143.
Abstract:
The mathematical model of general Fourier heat conduction law is discussed in the paper.Based on the hyperbolic heat conduction equation of non Fourier heat conduction law,an analytical solution of a semi infinite body has been derived under the firs...
Leukemia cell purging through photodynamic therapy with oligonucleotide modified by photosensitizer
Xu Chuanshan, Yu Qian, Wu Shiming, Tang Jianmin
2002, 26(2): 159-160.
Abstract:
It is still an important subject in hematology how to effectively purge leukemia cell in hematopoietic stem cell transplantation.The up to date failure of all pharmacological purging attempts has been promoting the development of alternative strategi...