Journals >Chinese Journal of Lasers
Contents
2003
Volume: 30 Issue 3
24 Article(s)
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Research Article
Experimental Research of Doughnut, a New Kind of Laser Trap
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The experimental method used to form doughnut laser trap through axicons and by extracting high order diffractive light component is introduced. It is demonstrated qualitatively that doughnut laser trap has higher axial trapping force than Solid laser trap. The centrical horizontal trap stiffness of doughnut laser trapThe experimental method used to form doughnut laser trap through axicons and by extracting high order diffractive light component is introduced. It is demonstrated qualitatively that doughnut laser trap has higher axial trapping force than Solid laser trap. The centrical horizontal trap stiffness of doughnut laser trap and solid laser trap is measured by the method of image analyzing. The result demonstrates that solid laser trap is more rigid. The escaping force of laser trap, varying corresponding to different laser power, is measured by fluid mechanical method. The result demonstrates that doughnut laser trap has higher escaping force, thus can manipulate particles with more stability. It is indicated that doughnut laser trap brings to lower thermal damnification, and helps to make best use of low magnification objective lens, and helps to develop double laser traps..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 211 (2003)
Experimental Research of Doughnut, a New Kind of Laser Trap
[in Chinese], and [in Chinese]
Galvanometric scanner is widely used in rapid prototyping systems. Due to the intrinsical nonlinear relationship between the deflection angles and the corresponding xy coordinates, the pillow shaped field distortion would be introduced. In the paper, the aberration mechanism is analyzed and the correction algorithm tGalvanometric scanner is widely used in rapid prototyping systems. Due to the intrinsical nonlinear relationship between the deflection angles and the corresponding xy coordinates, the pillow shaped field distortion would be introduced. In the paper, the aberration mechanism is analyzed and the correction algorithm to compensate for the field distortion is proposed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 216 (2003)
Experimental Study on the Laser Depolarization of Fog
[in Chinese], and [in Chinese]
Fog with the size of 5～50 μm is simulated with an ultrasonic atomizer. A He Ne laser source at 0.63 μm is used to investigate the degree of the depolarization of the backscattered wave from those tiny water drop. It is shown that the degree of depolarization characters of those man made fog have a gravity dependence inFog with the size of 5～50 μm is simulated with an ultrasonic atomizer. A He Ne laser source at 0.63 μm is used to investigate the degree of the depolarization of the backscattered wave from those tiny water drop. It is shown that the degree of depolarization characters of those man made fog have a gravity dependence in a specified direction, and demonstrated an opto electronic effect in the depolarization of the fog..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 219 (2003)
Study on the Theory of Super-structured Fiber Bragg Grating
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The spectral property of super structured fiber grating was analyzed with Fourier transposition. It′s conclusion was then compared with the results gotten form the deduction with coupled mode theory. The two outcomes were unified with each other in many aspects, when reflective ratio was low enough. Furthermore, it is The spectral property of super structured fiber grating was analyzed with Fourier transposition. It′s conclusion was then compared with the results gotten form the deduction with coupled mode theory. The two outcomes were unified with each other in many aspects, when reflective ratio was low enough. Furthermore, it is found that the interval Δ λ between two reflective peaks of sample fiber grating was related not only to the period p of grating, but also closely to sampling rate T. The result has already been proved by experiment..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 247 (2003)
Holography and Information Processing
Study on Working Principle and Graphic Distortion of Galvanometer Scanning in Laser Large Screen Displayer
[in Chinese]
In the paper, the working principle of graphic output by wise laser large screen displayer is introduced. By study on the working principle of galvanometer scanning and the relations between with the deflection angle of galvanometer and the scanning point of laser in large screen, the methods of correcting the graphic In the paper, the working principle of graphic output by wise laser large screen displayer is introduced. By study on the working principle of galvanometer scanning and the relations between with the deflection angle of galvanometer and the scanning point of laser in large screen, the methods of correcting the graphic distortion due to galvanometer scanning are investigated..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 263 (2003)
Laser Devices and Laser Physics
M2-factor of Hard-edge Apertured Laguerre-Gaussian Beams-Self-convergent Beam Width Method and Comparison with the Symptotic Analysis
[in Chinese], and [in Chinese]
The self convergent beam width method is used to study the beam parameter propagation and M 2 factor of two dimensional hard edge diffracted Laguerre Gaussian beams. The results are analyzed an compared with those calculated by using the asymptotic analysis. It is shown that essentially the self convergent beam width mThe self convergent beam width method is used to study the beam parameter propagation and M 2 factor of two dimensional hard edge diffracted Laguerre Gaussian beams. The results are analyzed an compared with those calculated by using the asymptotic analysis. It is shown that essentially the self convergent beam width method is based on the truncated second order moments determined by the power fraction and the two correspondence between the two methods is discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 231 (2003)
Laser Manufacturing
Experimental Study of Laser Milling on Marble
[in Chinese], and [in Chinese]
Experiments of laser milling were done on marble with YAG laser. The influence of the processing parameters on the laser milling amount and milling surface quality were studied systematically, and the experiments of different shapes were carried out with optimized processes.Experiments of laser milling were done on marble with YAG laser. The influence of the processing parameters on the laser milling amount and milling surface quality were studied systematically, and the experiments of different shapes were carried out with optimized processes..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 275 (2003)
Development of Six-axis Robot Off-line Programming in Laser Processing
[in Chinese], [in Chinese], and [in Chinese]
In laser processing, in order to solve the low efficient problems about in line programming of six axis robot, the method of off line programming has been put forward, and a detailed approach is presented. Off line programming can greatly enhance efficiency and facilitate the users.In laser processing, in order to solve the low efficient problems about in line programming of six axis robot, the method of off line programming has been put forward, and a detailed approach is presented. Off line programming can greatly enhance efficiency and facilitate the users..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 279 (2003)
Recognition and Detection of the Laser Sounding Signal for the Underwater Target Based on the Gabor Expansion
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The paper discusses the detection and cognition of the laser echo signal of underwater target, based on the ability of the Gabor expansion to localize signals. In virtue of the multiple correlation analysis for the expansion coefficient in local window, the detection method of peak value is founded. By taking the traceThe paper discusses the detection and cognition of the laser echo signal of underwater target, based on the ability of the Gabor expansion to localize signals. In virtue of the multiple correlation analysis for the expansion coefficient in local window, the detection method of peak value is founded. By taking the trace and characteristic value of the coefficient matrix as parameters to describe the reflecting ability of underwater target, the classified cognition of the target is carried out. Experimental results show that the effective target detection probability is 93.0% and the classified recognition probability is 83.2%..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 282 (2003)
Study on Laser Myocardial Revascularization Improving Myocardial Blood Microcirculation
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The paper reports the animal experiment that local myocardial blood flow is measured with the help of radioactive biomicrosphere. The result of research demonstrates that CO 2 laser myocardial revascularization with the help of the tailor made filter is effectual for improvement of myocardial blood microcirculation andThe paper reports the animal experiment that local myocardial blood flow is measured with the help of radioactive biomicrosphere. The result of research demonstrates that CO 2 laser myocardial revascularization with the help of the tailor made filter is effectual for improvement of myocardial blood microcirculation and myocardial ischemia. The paper analyses and explains some inconsistent phenomena in the research of laser myocardial revascularization according to the principle of laser myocardium interactions..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 285 (2003)
Laser Physics
Rate-equation-based VCSEL Thermal Model and Simulation
[in Chinese], [in Chinese], and [in Chinese]
A rate equation based VCSEL thermal model is established, which can simulate the features in the non dc operating regimes, namely, small signal and transient modulating condition. The model is apt to implement in conventional SPICE like circuit simulators, including PSPICE, and used to simulate key features of VCSEL. TA rate equation based VCSEL thermal model is established, which can simulate the features in the non dc operating regimes, namely, small signal and transient modulating condition. The model is apt to implement in conventional SPICE like circuit simulators, including PSPICE, and used to simulate key features of VCSEL. The results compare favorably to experimental data from two devices reported in the literature..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 193 (2003)
BBO Optical Parametric Oscillator with the Configuration of Walkoff-compensating Crystals and Noncollinear Dual-direction Pumping
[in Chinese], [in Chinese], and [in Chinese]
Non collinear cavity with dual direction pumping geometry and high output coupling mirror are used in BBO OPO resonators to ensure continuously tunable without changing optics. Total output energy of 41 mJ and highest conversion efficiency of 50% have been attained with tuning range of 0.4～2.0 μm, which is pumped by a Non collinear cavity with dual direction pumping geometry and high output coupling mirror are used in BBO OPO resonators to ensure continuously tunable without changing optics. Total output energy of 41 mJ and highest conversion efficiency of 50% have been attained with tuning range of 0.4～2.0 μm, which is pumped by a Nd∶YAG laser with energy of 80 mJ at 355 nm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 199 (2003)
High Efficiency Nd∶YAG Doubling Frequency Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Two kinds of frequency doubling methods by using KTP crystal are introduced. The first is frequency doubling in a folded cavity, and the second is achievement of second harmonic generation in a resonant ring cavity. In the latter method, using an 1 kHz Q switched Nd∶YAG laser with an average power of 50 W as the input Two kinds of frequency doubling methods by using KTP crystal are introduced. The first is frequency doubling in a folded cavity, and the second is achievement of second harmonic generation in a resonant ring cavity. In the latter method, using an 1 kHz Q switched Nd∶YAG laser with an average power of 50 W as the input light, a green light with average power of 17.5 W and harmonic conversion efficiency of 35% is obtained. The laser used for mini focus of laser rapid prototyping is demonstrated..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 203 (2003)
Precise Design of Circular-symmetrical Diffractive Optical Element for Beam Smoothing
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, by using the hybrid algorithm merging hill climbing with simulated annealing, the precise design of the circular symmetrical diffractive optical element (DOE) for beam smoothing is completed. By comparing between the designed results of different sampling interval on focal plane, it is found that the facIn this paper, by using the hybrid algorithm merging hill climbing with simulated annealing, the precise design of the circular symmetrical diffractive optical element (DOE) for beam smoothing is completed. By comparing between the designed results of different sampling interval on focal plane, it is found that the facticity of designed result is greatly influenced by the sampling intervals. During the designing process, it is insufficient to sample only according to the sampling theory. To get the faithful intensity distribution for beam smoothing, the sampling interval must be less than or equal to 1/2 of the traditional sampling interval. Only under this condition, both the intensity of samples and other points on focal plane can be controlled to meet the requirements of beam smoothing..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 206 (2003)
Experimental Research on Backward SRS Pumped by High Power KrF Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, high efficient backward stimulated Raman compression is obtained pumped by high power KrF laser using focused beam geometry. The pulse duration is compressed by 15 times with total energy conversion efficiency of 17%. Maximum 1 7 J pulse (1 5 ns) is obtained when pumped by 10J pulse (22 ns). The mechanisIn this paper, high efficient backward stimulated Raman compression is obtained pumped by high power KrF laser using focused beam geometry. The pulse duration is compressed by 15 times with total energy conversion efficiency of 17%. Maximum 1 7 J pulse (1 5 ns) is obtained when pumped by 10J pulse (22 ns). The mechanism of high efficient backward SRS in focused geometry is discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 223 (2003)
Research on the Fourier Numerical Algorithm of Focused Beam
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In simulation of focused beam propagation with arbitrary focal length, the traditional beam propagation algorithm based on Fast Fourier Transform will fail to give right results due to the limitation of the sampling theorem. A new algorithm is given, in which the factor of spherical wave front is removing explicitly. TIn simulation of focused beam propagation with arbitrary focal length, the traditional beam propagation algorithm based on Fast Fourier Transform will fail to give right results due to the limitation of the sampling theorem. A new algorithm is given, in which the factor of spherical wave front is removing explicitly. Thus the propagation of a focused beam could be evaluated indirectly from propagation of an unfocused beam. The results in two cases are connected inherently by Fresnel number, which plays a key role in focused beam propagation..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 227 (2003)
Carrier Phase Modified Temporal Characteristics of Few-cycle Guassian Pulses
[in Chinese], [in Chinese], and [in Chinese]
Carrier phase dependent characteristics of a few cycle chirp free Guassian pulse have been studied in the time domain. Expressions of the pulse energy W, center of gravity of the time 〈t〉, and effective pulse width τ eff have been deduced in terms of the carrier phase. Results suggest that the carrier phase takes effecCarrier phase dependent characteristics of a few cycle chirp free Guassian pulse have been studied in the time domain. Expressions of the pulse energy W, center of gravity of the time 〈t〉, and effective pulse width τ eff have been deduced in terms of the carrier phase. Results suggest that the carrier phase takes effect when the time width (FWHM) τ P of the pulse envelope becomes smaller than the period of the carrier oscillation period..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 236 (2003)
Materials and Thin Films
Influence of Ce3+ Ion on the Spectroscopic Properties of Er3+-doped Tellurite Glass
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The influence of Ce 3+ ions on the spectroscopic properties of Er 3+ doped tellurite glass was investigated in this work. It is found that the fluorescent intensity of 4I 13/2 level of Er 3+ ion is enhanced, stimulated emission cross section and FWHM of fluorescent peak are increased and upconversion intensity under 98The influence of Ce 3+ ions on the spectroscopic properties of Er 3+ doped tellurite glass was investigated in this work. It is found that the fluorescent intensity of 4I 13/2 level of Er 3+ ion is enhanced, stimulated emission cross section and FWHM of fluorescent peak are increased and upconversion intensity under 980 nm excitation is greatly suppressed in Er 3+ doped tellurite glass. This affect is due to energy cross relaxation from 4I 11/2 level of Er 3+ to 2F 7/2 level of Ce 3+ . Through empirical equation calculation, it is found that the lifetime of 4I 11/2 level of Er 3+ is greatly decreased by Ce 3+ co doping, while the lifetime decrease of 4I 13/2 is very small..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 267 (2003)
Absorption Spectra and Photofading Research of an Indium Phthalocyanine Dye
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An indium phthalocyanine dye dopped PMMA and PC thin film were obtained by a optical glass modul, which maybe used as a laser protective dye. The absorption spectra of chloroform solution, PMMA and PC films were studied. It was revealed that indium phthalocyanine monomer existed in the tested concentrations, there was An indium phthalocyanine dye dopped PMMA and PC thin film were obtained by a optical glass modul, which maybe used as a laser protective dye. The absorption spectra of chloroform solution, PMMA and PC films were studied. It was revealed that indium phthalocyanine monomer existed in the tested concentrations, there was an intense and sharp absorption at 694nm, which suited for laser protection. At the same time, the spectra were explained with its energy levels structure. In films, two strong and shouder absorption bands were observed in Q band, which were slightly hypsochromically or hypochromically shifted and wider compared with the solution absorption spectra. In order to obtain the same absorbance the dyes needed changed greatly. These phenomena can be explained that there were photofading in solutions and molecular aggregation in polymers. At the same time, based on the resulting fragments by EI MS, the mechanism of the photofading was proposed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 271 (2003)
Measurement and Metrology
Influence of Stress on Thermal Diffusivity by Laser Photothermal Technique
[in Chinese], [in Chinese], and [in Chinese]
A method of measuring thermal diffusivity by laser photothermal parallel detection technique is introduced when materials possess stress. According to amplitude of photothermal signal, thermal diffusivity can be determined by nonlinear fitting. The results show that diffusivity become small under stress existing. The sA method of measuring thermal diffusivity by laser photothermal parallel detection technique is introduced when materials possess stress. According to amplitude of photothermal signal, thermal diffusivity can be determined by nonlinear fitting. The results show that diffusivity become small under stress existing. The software of collecting data and the double difference circuit are designed, and the measurement accuracy is raised..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 252 (2003)
Experimental Method of Estimating Effective Laser Intensity by Use of the High-order Spectrum
[in Chinese], [in Chinese], and [in Chinese]
In this paper, based on the dispersion of grating in monochromator, the cutoff wavelength of getting harmonics is judged on the appearance of 2 nd spectrum (wavelength of 69.13 nm) of the 23 rd high order harmonic (wavelength of 34.56 nm); Accordingly, the efficiency laser intensity of producing X spectrum is estimatedIn this paper, based on the dispersion of grating in monochromator, the cutoff wavelength of getting harmonics is judged on the appearance of 2 nd spectrum (wavelength of 69.13 nm) of the 23 rd high order harmonic (wavelength of 34.56 nm); Accordingly, the efficiency laser intensity of producing X spectrum is estimated in virtue of the theory of high harmonic which is 1.007×10 14 W/cm 2 and the most photon energy is 32.817 eV, which are the basic data of studying the origin and intensity of the spectrum in the experiment..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 255 (2003)
Experimental Research on the Backscatter Characteristics from Surface Materials of Wall as Target for Laser Remote Detection of Gases
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this article, the characteristics of several surface materials of wall as target for laser remote detection of toxic and hazardous gases were described. The backscatter data were obtained by a novel measured method with one particular technique. By use of these data, the bidirectional reflectance distribution functiIn this article, the characteristics of several surface materials of wall as target for laser remote detection of toxic and hazardous gases were described. The backscatter data were obtained by a novel measured method with one particular technique. By use of these data, the bidirectional reflectance distribution function (BRDF) of these surface materials was calculated by comparing with that of the PTFE diffuse plate..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 259 (2003)
Optical Communication
Experimental Study on Interleaved Demultiplexer Based on Polarization Beam Interferometer
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel interleaved demultiplexer based on polarization beam interferometer is proposed. The configuration and basically principle were analyzed by means of birefringence crystal and polarization beam interferometer. With simple experiment, interleaver does separate DWDM odd and even channel into two groups with the poA novel interleaved demultiplexer based on polarization beam interferometer is proposed. The configuration and basically principle were analyzed by means of birefringence crystal and polarization beam interferometer. With simple experiment, interleaver does separate DWDM odd and even channel into two groups with the power equalization and satisfied with ITU T suggestions. The two channels isolations are 10.6 dB and 14.64 dB respectively, -1 dB bandwidth are 0.7 nm and 0.4 nm, respectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 239 (2003)
All-fiber Interleave Filter Using Mach-Zehnder-based Sampled Fiber Gratings
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel all fiber interleave filter using Mach Zehnder based sampled fiber gratings was proposed and fabricated. The operation principle of this device was introduced, and its performances were analyzed mathematically. In this proposed interleaver, the splitter ratio of coupler, the spectrum of sampled fiber grating anA novel all fiber interleave filter using Mach Zehnder based sampled fiber gratings was proposed and fabricated. The operation principle of this device was introduced, and its performances were analyzed mathematically. In this proposed interleaver, the splitter ratio of coupler, the spectrum of sampled fiber grating and path length difference of two arms are the three key parameters that decide the performances of the interleaver. The interleaver demonstrates channel spacing of 100 GHz..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 30, Issue 3, 243 (2003)
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