Table of contents

20 August 1995, Volume 4 Issue 8 Previous issue    Next issue

GENERAL

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PHASE TRANSITION PROPERTY OF THE BOSONIZED HUBBARD MODEL DING GUO-HUI (丁国辉), XU BO-WEI (许伯威) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  561-568.  DOI: 10.1088/1004-423X/4/8/001 Abstract ( 1309 )   PDF (154KB) ( 431 )   Using the bosonization method of one-dimensional fermion system, we discussed the bosonized Hamiltonian of the half-filling Hubbard model, and investigated the ground state and phase transition properties with the gaussian effective potential method of sine-Gordon field.

CLASSICAL AREAS OF PHENOMENOLOGY

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EXCITED-STATE NONLINEAR ABSORPTION AND ITS APPLICATION IN PHOTONIC TECHNOLOGY LI CHUN-FEI (李淳飞), SI JIN-HAI (司金海), YANG MIAO (杨淼), WANG YU-XIAO (王玉晓) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  569-580.  DOI: 10.1088/1004-423X/4/8/002 Abstract ( 1190 )   PDF (283KB) ( 435 )   The main achievements in our research on the physical phenomena of the excited-state nonlinear absorption in a molecular system and its applications in photonic technology are described. In the first part of this paper, some energy-level models and rate-equations are used to explain various mechanisms of the excited-state nonlinear absorption under differ-ent conditions, such as reverse saturable absorption caused by the triplet and/or the singlet excited-state absorption; saturable absorption due to the first and/or the second singlet excited-state absorption; and the excited-state nonlinear absorption induced by two-photon absorption. The experimental results for metal-organic and C60 materials irradiated by ps and ns laser pulses are consistent with the simulated curves of the transmittance versus flu-ences. In the second part, the applications of excited-state nonlinear absorption in photonic techniques including optical bistability, optical switching, optical limiting, optical modula-tion, optical logic and optical storage are introduced. The working principles of the photonic devices based on the excited-state nonlinear absorption are presented. The experimental characteristic curves are found in good agreement with the theoretical simulations for these devices.

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A CONTINUOUS COMPOUND FOUR-WAVE MIXING MECHANISM FOR SELF-PUMPED PHASE CONJUGATION IN BaTiO3 CRYSTALS XIE PING (谢平), DAI JIAN-HUA (戴建华), WANG PENG-YE (王鹏业), ZHANG HONG-JUN (张洪钧), LIN HONG (林红) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  581-594.  DOI: 10.1088/1004-423X/4/8/003 Abstract ( 1286 )   PDF (438KB) ( 363 )   A continuous compound four-wave mixing mechanism for sell-pumped phase conjugation in photorefractive crystals is presented. The coupled-beam equations of this mechanism are solved numerically when depletion of the forward going beam is neglected. The experiment in a Ce-doped BaTiO3 crystal is performed, with the stable phase conjugate reflectivity of as much as ≥80%. The curved high output phase conjugate intensity are explained using the numerical results.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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THE THRESHOLD, TRAPPED AND TRASITIONAL REGIONS OF NONLINEAR ION ACOUSTIC WAVE WANG WEN-QING (王文清), XIA MENG-FEN (夏蒙芬) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  595-600.  DOI: 10.1088/1004-423X/4/8/004 Abstract ( 1567 )   PDF (145KB) ( 387 )   The nonlinear effects of large amplitude ion acoustic wave are studied theoretically and experimentally, so as to obtain the amplitude threshold for producing the nonlinear effects, the half width of the trapped region and the transitional region width caused by collisions. The experimental results are in good agreement with the theoretical predictions.

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PERFORMANCE OF A COMPACT ECR SOURCE FOR MBE EQUIPMENT YAO XIN-ZI (姚鑫兹), HUANG YUN-HENG (黄运衡), JI TIAN-REN (季天仁), MENG LIN (蒙林), LIU HUA (刘华) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  601-605.  DOI: 10.1088/1004-423X/4/8/005 Abstract ( 1220 )   PDF (147KB) ( 443 )   A compact electron cyclotron resonance plasma source has been developed for molecular beaut epitaxy equipment. Faraday cup and Langmuir probe were used to measure the ion current densities, electron temperatures, ion densities, and plasma potentials. The ion current densities as function of pressure and microwave power have been studied.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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PHOTOLUMINESCENCE STUDY ON Hg1-xCdxTe THIN FILM IMPLANTED WITH As ION CHANG YONG (常勇), CHU JUN-HAO (褚君浩), TANG WEN-GUO (唐文国), SHEN WEN-ZHONG (沈文忠), LI ZI-YUAN (李自元), TANG DING-YUAN (汤定元), GUO SHI-PING (郭世平), YUAN SHI-XIN (袁诗鑫) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  606-611.  DOI: 10.1088/1004-423X/4/8/006 Abstract ( 1143 )   PDF (202KB) ( 434 )   Photoluminescence spectra of a series of MBE-grown Hg1-xCdxTe samples with the same mole fraction of about x≈0.39 have been measured at different temperatures from 5 to 100 K. By aid of the temperature and exciting laser power dependence of photoluminescence peak energy and relative intensity, as well as of the comparison with other measurements, four main structures dominating in the photoluminescence spectra are attributed to band to band, DoX, AoX and DoAo transitions. A deep donor state level located at about 8.5meV below the bottom of the conduction band has been observed and is determined to be due to the arsenic-occupied mercury vacancies. Two acceptor levels located at about 14.5 meV and about 31.5 meV above the top of the valance band have also been found from the measuements, which are identified as the mercury vacancies and As in anion site, respectively.

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RAMAN SCATTERING OF Dy/Y RARE EARTH SUPERLATTICE LIU DAO-ZHI (刘道志) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  612-616.  DOI: 10.1088/1004-423X/4/8/007 Abstract ( 1100 )   PDF (148KB) ( 435 )   We report the observations of Raman scattering of the TO phonon modes from the different layers in Dy/Y rare earth superlattices. It is found that helical phase lock-in transition at about 50 K in the Dy/Y superlattice is accompanied by the softening of TO phonons from both Dy magnetic layers and Y nonmagnetic layers.

GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS

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CHARGED STATIC CYLINDRICAL BLACK HOLE HUANG CHAO-GUANG (黄超光) Acta Physica Sinica (Overseas Edition), 1995, 4 (8):  617-630.  DOI: 10.1088/1004-423X/4/8/008 Abstract ( 1122 )   PDF (286KB) ( 521 )   The charged static eylindrical black hole solution of the Einstein-Maxwell equations with negative cosmological constant is obtained. The properties of the solution are analyzed. The first law of thermodynamics for the cylindrical black hole is written down. Unlike the Reissner-Nordstr?m black hole, its heat capacity is always positive.