TEMPORAL CHARACTERISTICS OF DECAY OF LIGHT-INDUCED ABSORPTION IN PHOTOREFRACTIVE BaTiO3 CRYSTALS

We report the observations of the decay processes of light-induced absorption in one undoped and two Ce-doped BaTiO₃ crystals. Two decay times were found, they had not a strong dependence on intensity in our experiment. We present a model with two different shallow trap centers to explain the experimental results. The theoretical and experimental resales agree well with each other. The light-induced absorption coefficients and decay times corresponding to the two shallow levels are also given.     

激光光谱学的现状与前景

一、学科的发展与趋向 激光光谱学是激光出现以后最活跃的光学研究领域之一.它的任务是充分利用激光的高强度、高单色性、相干性和方向性,解决传统光谱学难以解决成有待解决的一系列问题.例如,高分辨和超高分辨光谱,高激发态光谱以及超快过程(即高时间分辨)光谱等问题.　近二十年来,无论是光源、光谱方法或应用方面,激光光谱学都在快速地发展,总的趋势如下.(1)光谱分辨率愈来愈高 1970年是激光光谱学有较大突破的一年,当时用饱和吸收法获得了激光腔外气体的消多普勒加宽谱,观测了碘分子被多普勒加宽所淹没的超精细结构.谱线宽度为6MHz,分辨…     

TEMPORAL CHARACTERISTICS OF DECAY OF LIGHT-INDUCED ABSORPTION IN PHOTOREFRACTIVE BaTiO3 CRYSTALS

We report the observations of the decay processes of light-induced absorption in one undoped and two Ce-doped BaTiO₃ crystals. Two decay times were found, they had not a strong dependence on intensity in our experiment. We present a model with two different shallow trap centers to explain the experimental results. The theoretical and experimental resales agree well with each other. The light-induced absorption coefficients and decay times corresponding to the two shallow levels are also given.     

简并四波混频与位相复共轭(Ⅰ)

光学位相复共轭技术近年来在非线性光学研究的基础上得到迅速发展.这种技术的主要之点,是获得相对于给定光波而言,具有反演位相(或波阵面)的光波.这种技术在数学上相当于一种算符,经它的作用后光波电场的复数表示中的复数空间振幅将转变为其复共轭量,并因此而得名。 光学位相复共轭技术的发展是和光学信息的实时处理相联系的,首先是要设法补偿光波或图象在传播中引起的位相畸变.这样的努力可以追朔到六十年代末和七十年代初.那时,一方面事实上已经提出用实时全息方法产生反向波以补偿位相畸变,另一方面也有不少工作利用瞬态全息图来研究各种…     

液晶四波混频特性的探讨

本文提出并分析了液晶简并与二重简并四波混频的两种物理机制——来源于分子重新取向的非线性极化以及热致位相光栅。提出了区分两种机制的偏振鉴别法,获得了单纯来源于分子重新取向机制的简并与二重简并四波混频讯号。     

简并二能级系统受激光子回波的研究——一般理论及弛豫感生的光子回波

研究了简并二能级系统的受激光子回波效应。将密度矩阵以不可约球面张量元展开,在三阶微扰理论的基础上得到对应于不同入射光偏振配置的受激光子回波信号,并讨论了其特性。以j_a=j_b=1/2系统为例,讨论了在σ₊→σ₊→σ_-的偏振配置下的弛豫感生的光子回波。 关键词：     

INFLUENCE OF BEAM POLARIZATION ON THE PERFORMANCE OF A MUTUALLY PUMPED PHASE CONJUGATOR

The influence of polarization variation of a pump beam on the performance of a “bridge” mutually pumped phase conjugator has been investigated. The reflectivity, transmission, and response time were measured for different polarizations and different intensity rations of input beams. From these measured results, the variation behaviors of parameters of fourwave mixing interactions in the crystal are revealed.     

时间分辨简并四波混频中的量子拍频效应

本文严格处理了准简并二能级系统中时间分辨简并四波混频问题。指出在这种简并四波混频中同样可能存在量子拍频效应。分析了这种量子拍频效应的产生条件和特点。讨论了可能的应用。 关键词：     

金属有机电荷转移盐(CpFeBz)n[M(L)2](L=mnt或dmit)的合成及其三阶非线性光学性质

合成了两种类型共九个新的金属有机电荷转移盐(CpFeBz)_n[M(mnt)_2]和(CpFeBz)_n[M·(dmit)_2](M=Ni,Pd,Pt,Cu,Co;Cp代表环戊二烯基;Bz代表苯;mnt代表(?);dmit代表(?);n=1或2).通过元素分析IR和~1H NMR对化合物进行了鉴定.用简并四波混频的方法首次研究了金属有机电荷转移盐的三阶非线性光学性质.结果表明,这类金属有机电荷转移盐有较大的近共振三阶非线性光学响应.     

LIGHT-INDUCED ABSORPTION ENHANCEMENT IN C60 TOLUENE SOLUTION

Absorption enhancement induced by a pump beam of 532 nm in C₆₀ toluene solution has been observed and studied from 560nm to 63Onm, and the absorption cross section of its lowest triplet state has been determined in this wavelength range according to our theoretical model.