Contents
1985
Volume: 5 Issue 12
16 Article(s)
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Research Article
[in Chinese]
[in Chinese]
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 13 (1985)
Instrumentation, Measurement and Metrology
Contour generation using spatial filtering
LI YINGQUAN, and GU QUWU
A coherent optical method for generating contours from stereophotographs by using a grating as a spatial filter is proposed. The relationship between parallax and light amplitude distribution in the spectrum plane, the effect of spatial filtering and the final light amplitude distribution in the image plane are analyseA coherent optical method for generating contours from stereophotographs by using a grating as a spatial filter is proposed. The relationship between parallax and light amplitude distribution in the spectrum plane, the effect of spatial filtering and the final light amplitude distribution in the image plane are analysed theoretically. The superposition of the amplitude transmittances of the stereophotographs in the object plane of a 4f system, when illuminated with a beam of coherent light, will result in numerous sets of straight interference fringes in the speotrnm plane, with eaoh set ooresponding to a set of points with the same parallax, i. e., a contour line. When a grating is used to provide spatial filtering, only one Set of fringes is allowed to transmit through the grating, while others are blocked off. Then a contour will appear in the image plane of the system. Different grating spaoings oorespond to different contour positions and a change in the position of the grating will lead to bright or dark contours. Stright and circular contours are obtained by using two experimental models, a slope and a conio. Experimental results with contonrs in different positions and having different values of brightness are given in the paper. Because it is unnecessary to measure parallax point by point, the method has the advantage of quickness. In our experiment, two stereophotographs are superposed on one photosensitive plate incoherently to achieve amplitude addition so as to reduce the requirement on the system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1082 (1985)
Shadow Moire topography using cylindrical grating
YUAN YULIN
The mathematical expression is derived for the shadow Moire topography usinga cylindrical grating. Experimental photographs and theoretical curves drawn on a computer in accordance with the equation are presented. Experimental data are in reasonable agreement with the data derived from the photographs. The merit with tThe mathematical expression is derived for the shadow Moire topography usinga cylindrical grating. Experimental photographs and theoretical curves drawn on a computer in accordance with the equation are presented. Experimental data are in reasonable agreement with the data derived from the photographs. The merit with the use of cylindrical grating is that, it increases the measuring depth compared with ordinary Moire topography..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1090 (1985)
Lasers and Laser Optics
Some factors influencing efficiencies of self-sustained discharge transverse-flow CO2 lasers
XU JIHUA, CHEN LIYIN, CHU ZEXIANG, and WU ZHONGXIANG
Theoretical computations and analyses are made of the efficiencies of self-sustained discharge transverse-flow CO2 lasers. A model of one-dimensional steady flow, quasi-two dimensional discharge and three vibrational relaxing modes is used under various conditions of discharge, flow and cavity position in the flow direTheoretical computations and analyses are made of the efficiencies of self-sustained discharge transverse-flow CO2 lasers. A model of one-dimensional steady flow, quasi-two dimensional discharge and three vibrational relaxing modes is used under various conditions of discharge, flow and cavity position in the flow direction. Efficiencies of the cascade processes (input electrical energy-energy of upper vibrational levels, energy of upper vibrational levels-output laser energy, and input electrical energy-output laser energy, are given as frictions of electrode width, gas-fiow velocity and cavity position, A theoritioal reference is thus provided for properly selecting laser parameters, such as discharge conditions, flow parameters and cavity configurations..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1097 (1985)
Computer modeling for a lead vapor laser
XIA TIEJUN, YAO ZHIXIN, WANG YONGJIANG, and SUN WEI
A computer model has been built to simulate the excitation process of a lead vapor laser results obtained from the model agree with experiments. The calculation indicates that the main parameter effecting laser output power is the peak electron temperature, while the limitation of repetition rates is related to the iniA computer model has been built to simulate the excitation process of a lead vapor laser results obtained from the model agree with experiments. The calculation indicates that the main parameter effecting laser output power is the peak electron temperature, while the limitation of repetition rates is related to the initial electron density..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1105 (1985)
Nonlinear Optics
Stimulated Raman scattering with cascade pumping in high pressure H2
LOU QIHONG, YUAN YIFENG, and WANG ZHIJIANG
The stimulated Raman scattering pulse from a high-pressure H2 Raman cell pumped by a XeCl excimer laser was used to pump another short high-pressure H2 Raman cell. The higher order Stokes lines were enhanced successfully by using this cascade pumping configuration.The stimulated Raman scattering pulse from a high-pressure H2 Raman cell pumped by a XeCl excimer laser was used to pump another short high-pressure H2 Raman cell. The higher order Stokes lines were enhanced successfully by using this cascade pumping configuration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1069 (1985)
Acousto-optic optical bistability in different states of acoustic field
DONG XIAOYI, ZHANS XIAOJIE, and SHEN QIUGIN
Characteristics of A-O optical bistability with different acoustic travelling-wave coefficient a and effects of acoustic field state on the bistability are analysed. It is pointed out that for A-O bistability to be of practical usefulness the acoustic field should have a specific αcoefficient. When α=1 (i.e., pure acouCharacteristics of A-O optical bistability with different acoustic travelling-wave coefficient a and effects of acoustic field state on the bistability are analysed. It is pointed out that for A-O bistability to be of practical usefulness the acoustic field should have a specific αcoefficient. When α=1 (i.e., pure acoustic standing-wave field) the A-O bistability becomes useless. Experimental results are in agreement with theories..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1074 (1985)
Physical Optics
Four-wave mixing in a copper vapor laser
LIN FUCHENG, LI SHIFANG, and HU QIQUAN
Four-wave mixing was observed in the active medium of a copper vapor laser. The reflection coefficient was found to be over 100% for the green light in the device with an average output power of 2 W.Four-wave mixing was observed in the active medium of a copper vapor laser. The reflection coefficient was found to be over 100% for the green light in the device with an average output power of 2 W..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1127 (1985)
Rapid Communications
Determination of pulse shape asymmetry in a CW synchronously pumped dye laser using the method of spectrum-resolved SHG correlation
BAO XIAOYI, GUAN XINAN, LU FUYUN, and YUAN SHUZHOUG
We have determined the pulse shape asymmetry in a synchronously pumped dye laser using the method of spectrum-resolved SHG correlation. In this paper, we first present the basic principle of spectrum-resolved SHG correlation, and then analyse the possibility of determination of the pulse shape asymmetry in a CW synchroWe have determined the pulse shape asymmetry in a synchronously pumped dye laser using the method of spectrum-resolved SHG correlation. In this paper, we first present the basic principle of spectrum-resolved SHG correlation, and then analyse the possibility of determination of the pulse shape asymmetry in a CW synchronously pumped dye laser by this method. The experimental results were found to be in good -agreement with the results of our analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1130 (1985)
A new analytic method for calculating waveguide dispersion of single-mode fibers
WANG ZIHUA, and ZHANG YILONG
A new analytic method is developed for calculating the waveguide dispersion of single-mode fibers by using its field distribution. For step-index single-mode fibers, a waveguide dispersion formula is deduoed which is more accurate than that given by Sansonetti [2].A new analytic method is developed for calculating the waveguide dispersion of single-mode fibers by using its field distribution. For step-index single-mode fibers, a waveguide dispersion formula is deduoed which is more accurate than that given by Sansonetti [2]..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1134 (1985)
Spectroscopy
Theoretical analysis of asymmetric pulse shapes in synchronously pumped dye lasers
BAG XIAOYI, and GUAN XINAN
By expanding the gain of the mode-locked equation to the third order, we have solved the equation with the aid of the La grange muliplier method and obtained asymmetric pulse shapes in synchronously pumped dye lasers. We can thus give qualitative and quantitative accounts for the asymmetric factor μ.By expanding the gain of the mode-locked equation to the third order, we have solved the equation with the aid of the La grange muliplier method and obtained asymmetric pulse shapes in synchronously pumped dye lasers. We can thus give qualitative and quantitative accounts for the asymmetric factor μ..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1057 (1985)
Two-photon spectra of neutral Barium in high-lying states
WU DONGHONG, ZHANG ZAIXUAN, MI XIN, LI FANGDAI, and DING DAJUN
Barium atoms pumped by a dye laser can absorb two photons and transit to high-lying states. By using a heat diode to detect ionization signals, we obtained three even-parity Rydberg series 6 ns 1S0(n=11～46), 6snd 1D2(n =9～60) and 6snd3D2 (n=10～28), as well as five perturbing levels 5d833D2, 5d83, 5d8s 1d2,5d7d 3F2, 5d7Barium atoms pumped by a dye laser can absorb two photons and transit to high-lying states. By using a heat diode to detect ionization signals, we obtained three even-parity Rydberg series 6 ns 1S0(n=11～46), 6snd 1D2(n =9～60) and 6snd3D2 (n=10～28), as well as five perturbing levels 5d833D2, 5d83, 5d8s 1d2,5d7d 3F2, 5d7d3 P0 and 5d7d 1D2. The Lu-Fano plot is used in our discussion..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1064 (1985)
Thin Films
A simple analytical method for determining the optical gap of amorphous silicon films
ZHU WEIJIA
For material research and device design of amorphous silicon solar cells, it is required to determine the refractive indices, thickness and absorption coefficients of a-Si films. Taking interferences and substracte effects into account, we propose a simple analytical method that allows us to determine the thickness, reFor material research and device design of amorphous silicon solar cells, it is required to determine the refractive indices, thickness and absorption coefficients of a-Si films. Taking interferences and substracte effects into account, we propose a simple analytical method that allows us to determine the thickness, refractive index and absorption coefficient of a film from the usual transmittance spectrum at normal incidence. As an example, we calculated the optical gap of a-Si:H and a-SiC:H films..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1111 (1985)
Coupling system of Grin rod lenses in WDM
LIU DEMING, LIU WENDA, and LIU SHUQI
The theory of matrix-optics is used to discuss the imaging characteristics of Grin rod lenses. Formulas for designing low-loss coupling systems are developed and effects of parameters of a coupling system on the coupling loss are analyzed.The theory of matrix-optics is used to discuss the imaging characteristics of Grin rod lenses. Formulas for designing low-loss coupling systems are developed and effects of parameters of a coupling system on the coupling loss are analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 5, Issue 12, 1118 (1985)
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