Contents
1984
Volume: 4 Issue 7
16 Article(s)
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Research Article
Fourier Optics and Signal Processing
Ultrahigh-speed photography of interference patterns and shadowgraphs by using encoding gratings
XU YUGUANG, CHEN SHOUHUA, and RONG ZHONGHUA
A laser beam is split into several sub-beams, each of which has different delay time and is encoded by using a grating placed in different azimuth. After converging by means of a series of reflectors, these sub- beams become one beam again which is used to diagnose the object through holographic interference and hologrA laser beam is split into several sub-beams, each of which has different delay time and is encoded by using a grating placed in different azimuth. After converging by means of a series of reflectors, these sub- beams become one beam again which is used to diagnose the object through holographic interference and holographic shadowgraph. When the hologram is decoded, a set of interference patterns or shadowgraphs corresponding to different moments can be obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 600 (1984)
Instrumentation, Measurement and Metrology
Experimental measurement of stray light in holographic concave grating monochromators
ZHU YAYI, YIN JIANPING, Gu HUAJIAN, and DU YABIN
This article deals with the resources of the stray light in holographic concave grating monochromators. A new plan of measuring the stray light is suggested. The linear calibration in large-order-scale is solved by using light intensity recursion, real environment calibration and photon counting technique. The measurinThis article deals with the resources of the stray light in holographic concave grating monochromators. A new plan of measuring the stray light is suggested. The linear calibration in large-order-scale is solved by using light intensity recursion, real environment calibration and photon counting technique. The measuring limit of order 10-12 is obtained under the condition of the sampling time of the photon counter in one second. This article introduces a new designing idea for eliminating the error caused by the fluctuation of light source intensity and for improving the precision and accuracy of experiment. Finally, the measurement results of the stray light in the monochromatic system of the Raman spectroscopic instrument designed and produced by our institute are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 577 (1984)
Application of crystal intereference figures in conoscope to phase measurement
LIU LIREN
A new type of intensity spatial filter, based on the polarization interference figure from a crystal under conoscope is developed, and its application to the phase measurement in Fourier-transform quasi-interferometry is presented. This method does not require any Fourier-transforming lenses and masks for spatial filteA new type of intensity spatial filter, based on the polarization interference figure from a crystal under conoscope is developed, and its application to the phase measurement in Fourier-transform quasi-interferometry is presented. This method does not require any Fourier-transforming lenses and masks for spatial filtering. Various configurations are introduced and their performances are analysed. Some contour-fringes systems may be produced and even with background fringes. Several examples of experiments are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 582 (1984)
Magneto-optic modulation and measurement of Faraday rotation
LIU GONGQIANG, and LIU XIANGLIN
Main properties of magneto-optic modulators with single crystal films of garnets, the basic principle and the experimental installation of the measurement of Faraday rotation angle θ by means of the frequency doubling method of magneto-optic modulation are described. The means and merits of the measurement are presenteMain properties of magneto-optic modulators with single crystal films of garnets, the basic principle and the experimental installation of the measurement of Faraday rotation angle θ by means of the frequency doubling method of magneto-optic modulation are described. The means and merits of the measurement are presented, the results measured are discussed, and the measuring error is analysed. The Faraday rotation angle θ measured with the new moans is not effected by the light intensity change of a laser source and rnistable factors of other devices in a optical circuit, so that the measuring precision is ±0,020°..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 588 (1984)
The measurement of index profile in gradient index rod by wedge sample method
CHEN ZOUSHENG, and GAO YINGJUN
The sample to be measured is processed into a wedge slab. The interference pattern, which is related to the wedge angle, obtained by this method is a group of eccentric ring fringes. The advantage of this technique is that the absolute refractive index profile of a sample can be obtained from the interference film usinThe sample to be measured is processed into a wedge slab. The interference pattern, which is related to the wedge angle, obtained by this method is a group of eccentric ring fringes. The advantage of this technique is that the absolute refractive index profile of a sample can be obtained from the interference film using a standard interference instrument. The principle is analysed and its measuring errors are disoussod. The index profiles for some samples have been measured and their eccentric interference patterns and the results from data processing are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 593 (1984)
Lasers and Laser Optics
Free electron laser using the Smith-Purcell effect
CHEN JIANWEN, FU SHUFEN, and ZHANG DAKE
In this article, principle of the free electron laser using the Smith-Purcell effect is discussed. Influence of using a grating with variable space frequency upon radiation is studied. The calculation shows that if such a grating is adopted and its operating parameters are selected adequately, the threshold value of puIn this article, principle of the free electron laser using the Smith-Purcell effect is discussed. Influence of using a grating with variable space frequency upon radiation is studied. The calculation shows that if such a grating is adopted and its operating parameters are selected adequately, the threshold value of pumping electric current intensity is expected to decrease and the raidation power increase..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 607 (1984)
Polarization properties of an anisotropic cavity and Stokes polarization vector
GUO GUANGCAN
Stokes vector has been used to deal with the polarization properties of anisotropio cavities, including both active and passive cavities. The equation of motion of Stokes polarization vector is derived in an anisotropio cavity in which the gain coeffecient of active medium, the dielectric coeffecient and the loss of caStokes vector has been used to deal with the polarization properties of anisotropio cavities, including both active and passive cavities. The equation of motion of Stokes polarization vector is derived in an anisotropio cavity in which the gain coeffecient of active medium, the dielectric coeffecient and the loss of cavity all are anisotropic. Analytic expressions for the eigen-states of polarization, eigen-frequencies and frequency splitting axe given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 612 (1984)
Nonlinear Optics
Investigation of time character of backward wave in degenerate four-wave mixing
WU CUNKAI, CHOU FENG, and WANG ZHIYING
By using SH of a Q-switched Nd:YAG laser as the exciting pulse with FWHM of 10 ns, the time character of the backward waves were demonstrated for both transparent and absorbing media. The experimental results show that when the duration of the exciting pulses is considerably greater than the characteris tic time T = ∧/By using SH of a Q-switched Nd:YAG laser as the exciting pulse with FWHM of 10 ns, the time character of the backward waves were demonstrated for both transparent and absorbing media. The experimental results show that when the duration of the exciting pulses is considerably greater than the characteris tic time T = ∧/v(where A is the wavelength of the laser-induced acoustic wave; v is the sound velocity), the oscillating property of the backward wave disappears, it decays exponentially. The experimental results have been discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 642 (1984)
Third harmonic generation in Na-metal vapor
QIU PBIHUA, LI QUN, and WANG WENGYAO
By using the infrared picosecond pulse train of mode-locked laser, we observed the generation of third harmonic picosecond pulse at wavelength 3518 A in phase-matched gas-mixture of Na and Xe in a heat-pipe oven. The third harmonic light has been achieved to a power of 2.5 megawatt. Conversion efficiency from the fundaBy using the infrared picosecond pulse train of mode-locked laser, we observed the generation of third harmonic picosecond pulse at wavelength 3518 A in phase-matched gas-mixture of Na and Xe in a heat-pipe oven. The third harmonic light has been achieved to a power of 2.5 megawatt. Conversion efficiency from the fundamental to the third harmonic is 5 × 10-4..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 650 (1984)
Physical Optics
Modes equations for optical waveguides with Fermi index profile
FAN JUNQING, and DONG HECHAO
The characteristics of Fermi index profile have been analysed. It is shown that the quasi-step-graded index profile can be approximated by Fermi index profile. The equations of modes for planar optical waveguides with Fermi index profile have been obtained. The data calculation and the comparison between theory and expThe characteristics of Fermi index profile have been analysed. It is shown that the quasi-step-graded index profile can be approximated by Fermi index profile. The equations of modes for planar optical waveguides with Fermi index profile have been obtained. The data calculation and the comparison between theory and experimental results show that the characteristics of dispersion for optical waveguides with Fermi index profilecan be excellently determined. The accuracy is better than the approximation of Step index profile..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 628 (1984)
The dispersion of single mode optical fibers with arbitrary refractive index profiles
ZHOU WENJUN
This paper presents a method for calculating the dispersion of single mode optical fibers (SMOF) with arbitrary refractive index profiles. The dimensionless parameter called "optical dimension" of the fiber is introduced, from which a new dispersion formula of SMOF is derived. All the parameters in the formulThis paper presents a method for calculating the dispersion of single mode optical fibers (SMOF) with arbitrary refractive index profiles. The dimensionless parameter called "optical dimension" of the fiber is introduced, from which a new dispersion formula of SMOF is derived. All the parameters in the formula are calculated by the variation-finite element method[1] or with the Sellmeier formula[2]. Using program compiled from this calculation, the dispersion curves of SMOF with power-law refractive index profiles haye been determined at two low-loss windows, and 1.55 μm，and the effects of the refractive index dip at the core center on the dispersion in a step index SMOF have been investigated. The method can also be applied to the investigation of new kinds of optical fibers, and for obtaining significant information for the design, fabrication and measurement of SMOF..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 632 (1984)
Rapid Communications
Spectrum analysis of human blood flow Doppler signals with a time-spatial converter
YING XUANTONG, GHEN HUIPENG, ZHAO HuANQING, JIA YUruN, and YE GUOFEN
A method for spectrum analysis of human blood flow Doppler signals with an amplitude modulated grating as a time-spatial converter is reported. The experimental results are consistent with the theoretical analysis. This method possesses the advantages of fast multichannel parallel processing and large capacity. The facA method for spectrum analysis of human blood flow Doppler signals with an amplitude modulated grating as a time-spatial converter is reported. The experimental results are consistent with the theoretical analysis. This method possesses the advantages of fast multichannel parallel processing and large capacity. The facilities are simple and compact..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 656 (1984)
A unify method for extinction processing in atomic absorption and resonant fluorescent spectrometry
LIN YINGRONG
This paper introduces a new method which can obtain the extinction value linear to the concentration for the atomic absorption spectrometry (AAS) and atomic resonant fluorescent spectrometry (ARFS). The modeling experimental results exhibit that the measurement sensitivity is increased obviously too with this method. WThis paper introduces a new method which can obtain the extinction value linear to the concentration for the atomic absorption spectrometry (AAS) and atomic resonant fluorescent spectrometry (ARFS). The modeling experimental results exhibit that the measurement sensitivity is increased obviously too with this method. When the ARFS instead of AAS is used, not only the expression covention of the measure in extinction value is retained and there are also the property which the continuous radiant source and the lower resolution, monochromator applicable in ARFS, thus this unify processing method of extinction data exhibits some potential superiority..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 663 (1984)
Crossed beam chemiluminescence of O(3P) +NO reaction
XIE XIAOXIANG, ZHANG LIMING, QIU YUANWU, and LIU SONGHAO
The crossed beam chemiluminescence of O(3P)+NO→NO2+hv elementary reaction has been observed. The ground state oxygen atoms are produced by a microwave discharge in O2. Continuous spectra in the 4000-9666A region have been obtained. Dependence of the emission intensities on the NO flux is linear. Assuming the reaction oThe crossed beam chemiluminescence of O(3P)+NO→NO2+hv elementary reaction has been observed. The ground state oxygen atoms are produced by a microwave discharge in O2. Continuous spectra in the 4000-9666A region have been obtained. Dependence of the emission intensities on the NO flux is linear. Assuming the reaction obeys adiabatic correlation, the "chemiluminesecence should be due mainly to the transition 2B1→2A1 of NO2 molecules. This experimental result is in agreement with the theoretical calculation by Grangi et al...
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 668 (1984)
Spectroscopy
The spectral and lasing properties of several new dyes in ultraviolet region
YU ZHENXIN, YUAN YONGAN, WANG HEZHOU, GAO ZHAOLAN, and LOU YUNKANG
Four new 7-alkoxy-4-methyl coumarin dyes and their absorption spectra, fluorescence spectra and lasing properties are studied. In comparison with the fluorescence peak of coumarin dye 4MU, those of the new coumarins shifted about 60 nm to the short wavelength side. These four new dyes give laser emission in the UV regiFour new 7-alkoxy-4-methyl coumarin dyes and their absorption spectra, fluorescence spectra and lasing properties are studied. In comparison with the fluorescence peak of coumarin dye 4MU, those of the new coumarins shifted about 60 nm to the short wavelength side. These four new dyes give laser emission in the UV region. The laser tunable range and energy conversion efficiency have been determined. Using time-resolved techniques we have observed their kinetic fluorescence and determined the relevant fluorescence life-time..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 7, 621 (1984)
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