Table of contents

20 November 1994, Volume 3 Issue 11 Previous issue    Next issue

ATOMIC AND MOLECULAR PHYSICS

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SYSTEMATIC STUDY OF POLARIZATION OF TWO-PHOTON ABSORPTION IN SYMMETRY ASSIGNMENTS LIU YAO-MING (刘耀明), LIN MEI-RONG (林美荣), PAN XIAO-NING (潘潇宁), ZHANG BAO-ZHENG (张包铮), CHEN WEN-JU (陈文驹) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  801-808.  DOI: 10.1088/1004-423X/3/11/001 Abstract ( 1349 )   PDF (182KB) ( 495 )   In this paper, we have systematically analyzed the degenerate and nondegenerate two-photon polarization ratios of various point groups. We present the maximum of symmetry assignments of two-photon transition with the combination of degenerate and nondegenerate two-photon absorption. These results provide the theoretical basis for the experimental assignments.

CLASSICAL AREAS OF PHENOMENOLOGY

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EFFECTS OF MICROSTRUCTURES WITH DIMENSIONS SMALLER THAN OPTICAL WAVELENGTH ON SINGLE GROOVE DIFFRACTION Lü HUI-BIN (吕惠宾), R.E.BURGE, D.N.QU, X.YUAN Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  809-813.  DOI: 10.1088/1004-423X/3/11/002 Abstract ( 1236 )   PDF (154KB) ( 378 )   The experimental results showed that the microstructures of defects on the edges and walls of the single groove with their dimensions smaller than the wavelength of the incident light can produce effects not only on the diffraction of different polarization light but also on the symmetry of both positive and negative diffraction orders. It is possible to cause the narrow peaks with opposite directions appearing at corresponding positions on the two diffraction intensity curves when the polarization directions of the incident light are perpendicular to each other, and to cause the diffraction peaks to be asymmetric when the incident light for the two curves is of the same polarization direction.

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PHASE MATCHING AND DISTRIBUTION OF OPTICAL VORTICES IN THREE COUPLING DEGENERATE GAUSS-LAGUERRE MODES WANG KAI-GE (汪凯戈) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  814-820.  DOI: 10.1088/1004-423X/3/11/003 Abstract ( 1177 )   PDF (208KB) ( 772 )   We analyze the coupling equation for three degenerate Gauss-Laguerre modes in laser. For the multimode operation, there is a phase matching relation from which the distribution of optical vortices in the transverse patterns of optical field can be determined.

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NONLINEAR EXCITED STATE ABSORPTION IN CADMIUM-PORPHYRIN-LIKE SI JIN-HAI (司金海), YANG MIAO (杨淼), WANG YU-XIAO (王玉晓), ZHANG LEI (张雷), LI CHUN-FEI (李淳飞), WANG DUO-YUAN (王夺元), DONG SHI-MING (董世明), SUN WEN-FANG (孙文芳) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  821-827.  DOI: 10.1088/1004-423X/3/11/004 Abstract ( 1068 )   PDF (180KB) ( 452 )   Nonlinear absorption at 532 nm in a cadmium texaphyrin solution has been studied using 8ns and 23ps laser pulses. The experiments show that reverse saturable absorption occurs in the nanosecond case. For picosecond pulses, RSA occurs only at low fluences, and saturable absorption occurs at high fluences. A six-level model is proposed to explain these nonlinear absorption effects. Several photophysical parameters of excited states for cadmium texaphyrin, such as absorption cross-sections at 532nm and lifetime, have been evaluated by fitting theoretical calculations with the experimental results.

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STUDY ON LIGHT LOCALIZATION OF ONE-DIMENSIONAL DISORDERED MULTILAYER HU WEI (胡炜), ZHANG YOU-LONG (张有珑), ZHANG DAO-ZHONG (张道中), LI ZHAO-LIN (李兆霖), CHENG BING-YING (程丙英), YANG GUO-ZHEN (杨国桢) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  828-835.  DOI: 10.1088/1004-423X/3/11/005 Abstract ( 1297 )   PDF (240KB) ( 446 )   Antimonite and cryolite are used as the high and low refractive index coating materials to be evaporated alternately to the glass substrates. All cryolite layers have the same thickness d/4na, and the thickness of antimonite layers varies randomly around an average value d/4nb, with d=650nm, na and nb their refractive indices. Three kinds of multilayer are prepared, they possess the same degree of thickness disorder, but different total lengths, i.e., 10, 15 and 21 perioda. We measure the transmission and reflection spectrum after the light passing through these multilayers. The exponential intensity variation versus total length is experi-mentally demonstrated, and the light localization length is then obtained. Our experimental results can be fitted very well with the numerical simulation. Based on the measured and calculated localization length, the effects of phase coherent: Bragg reflection and Anderson localization are discussed.

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

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THE 2D LOCALIZED MODES OF BIPOLARON IN cis-POLYACETYLENE LI ZHAN-JIE (李占杰), AN ZHONG (安忠), YAO KAI-LUN (姚凯伦) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  836-842.  DOI: 10.1088/1004-423X/3/11/006 Abstract ( 1160 )   PDF (160KB) ( 378 )   The localized vibrational modes around a bipolaron in cis-(CH)x are studied by using a two-dimensional extension of the SSH model that includes the bond-bending term. A number of additional modes have been found, compared with the results based on the standard SSH model The amplitudes of the two directions (x and y direction) are comparable for most of the modes as in the trans-(CH)x case. The number of localized modes and their frequencies depend not only on the coupling constant, but also on the bond-bending term and the parameter t1 in removing the degeneracy of the ground state.

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ON THE SUPERCONDUCTING MECHANISM OF K3C60 AND Ba1-xKxBiO3 ZHANG LI-YUAN (章立源), ZHOU YUN-SONG (周云松), JIN GUANG-HAI (金光海) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  843-848.  DOI: 10.1088/1004-423X/3/11/007 Abstract ( 1443 )   PDF (182KB) ( 361 )   A superconducting mechanism for K3C60 and Ba1-xKxBiO3 has been suggested. This is the combining picture of the Cooper pair and the Ogg pair. Numerical calculations within the framework of this picture have been done for K3C60 and Ba1-xKxBiO3, and the overall consistency with the experimental data of superconducting properties is good.

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THEORY OF OPTICAL WAVE COUPLING IN THE PRESENCE OF MAGNETOSTATIC SURFACE WAVES WANG QI (王奇), WEN GUO-JUN (文国军), CAI YING-SHI (蔡英时) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  849-860.  DOI: 10.1088/1004-423X/3/11/008 Abstract ( 1160 )   PDF (279KB) ( 356 )   The general expression of magneto-optical permittivity tensor including the Faraday and Cotton-Mouton effects is derived and the coupled wave equations for the optical modes propagating in an arbitrary direction with respect to the magnetostatic surface wave are obtained. The optical multimode coupled wave equations will reduce to the bi-mode ones in the phase-matching conditions. The behaviors of four types of important optical bi-mode coupling are discussed and some new results are obtained. In the limits of $\alpha$ = 0 and $\pi$/2, all results obtained reduce to those reported in the literature.

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CRYSTALLIZATION OF DIELECTRIC SPHERES IN LASER STANDING WAVE FIELD CHENG BING-YING (程丙英), HU WEI (胡炜), YANG JUN-HUI (杨君慧), LI ZHAO-LIN (李兆霖), ZHANG DAO-ZHONG (张道中), YANG GUO-ZHEN (杨国桢) Acta Physica Sinica (Overseas Edition), 1994, 3 (11):  861-869.  DOI: 10.1088/1004-423X/3/11/009 Abstract ( 1208 )   PDF (369KB) ( 464 )   Experimental study on crystallization of polystyrene spheres and SrTiO3 particles in laser standing wave field is presented. The diameter of polystyrene, which are able to be trapped, is 7 times smaller than that reported by Burns, the corresponding lattice constant is reduced to 1.5 μm. The crystallization effect of SrTiO3 particles with a refractive coastant of 2.5 in the visible range is observed for the first time. Based on the results above we believe that it is possible to construct photonic crystal with lattice constant extended to visible wave range by this method.