非线性光学及其若干新进展

扼要介绍了非线性光学的基本概念及其最近10年来在飞秒激光，半导体材料，光纤通信和光信息存储等若干方面的研究进展。     

Modification of a YBa2Cu3O7—δ Thin Film Using an Atomic Force Microscope

A YBa2Cu3O7-δ thin film is modified by a probe electric field of an atomic force microscope to form a ridge with the width of only a grain cell.The modification varies with the operation parameters of the bias voltage,the moving velocity of the probe and the ambient humidity.Energy dispersive spectroscopy analysis shows only oxygen deficiency in the modified YBCO thin film.As a result,the suppressed superconductivity was found in the junction crossing the ridge.     

Phase Dependence of Fluorescence Spectrum of a Two-Level Atom in a Trichromatic Field

We examine the phase-dependent effects in resonance fluorescence of a two-level atom driven by a trichromatic modulated field. It is shown that the fluorescence spectrum depends crucially on the sum of relative phases of the sideband components compared to the central component, not simply on the respective phases. The appearance or disappearance of the central peak and the selective elimination of the sideband peaks are achieved simply by varying the sum phase. Once the sum phase is fixed, the spectrum keeps its features unchanged regardless of the respective relative phases.     

对中学物理"难学难教"现象分析

中学物理“难学难教”似乎己成为多数物理教师和学生的共识，那么物理“难学难教”的涵义是什么？中学物理包括初中物理和高中物理，是不是初中物理和高中物理都存在“难学难教”的现象？笔者做过一次问卷调查，调查对象为初中的初二、初三两个年级学生和高中的高一、高二、高三三个年级学生．调查的内容是：在数学、物理、化学三科中，你认为哪一科最难学？哪一科比较难学？哪一科容易学？认为物理最难、比较难、容易的三项统计结果如表1所示。     

Clock recovery from NRZ data at 10 Gb/s using SOA loop mirror and mode-locked fiber ring laser based on SOA

All-optical clock recovery from non-return-to-zero (NRZ) data using an semiconductor optical amplifier (SOA) loop mirror and a mode-locked SOA fiber laser is firstly schematically explained and experimentally demonstrated at 10 Gb/s. Furthermore, the pulse quality of the recovered clock is effectively improved by using a continuous-wave (CW) assist light in the gain region of SOA, through which the amplitude modulation is reduced from 57.2% to 8.47%. This scheme is a promising method for clock recovery from NRZ data in the future all-optical communication networks.     

一维磁光光子晶体的光学特性研究

详细推导了光在斜入射情况下通过磁光介质的4×4传输矩阵,研究了一维磁光光子晶体的光学特性.研究表明,由于光强主要局域在磁光介质层,波长位于光子禁带长波长带边的光通过磁光光子晶体所产生的法拉第旋转角比短波长带边产生的法拉第旋转角大得多.当光以TM偏振入射时,随着角度增大带边光产生的法拉第旋转角逐渐减小;而在TE偏振情况下,带边光产生的法拉第旋转角却随着角度的增大逐渐增大.     

广义椭圆积分的两个不等式

研究了函数△_p(r)=(E_p-(r')~pK_p)/(r~p)-(E'_p-r~pK'_p)/((r')~p)的单调性和凸性并给出了该函数的两个不等式,其中K_p和E_p分别是第一型和第二型广义椭圆积分.     

两类整环在w-算子下的刻画

通过对SM整环中准素w-理想与w-互素理想的讨论,证明了R是Krull整环当且仅当R是SM整环,w-dim(R)=1,且每个p-准素w-理想是素理想p的幂的w-包络.同时,运用w-算子,辅以t-,v-算子给出了π-整环的一些新的等价刻画.     

Optical bistability induced by quantum coherence in a negative index atomic medium

Bistability behaviors in an optical ring cavity filled with a dense V-type four-level atomic medium are theoretically investigated. It is found that the optical bistability can appear in the negative refraction frequency band, while both the bistability and multi-stability can occur in the positive refraction frequency bands. Therefore, optical bistability can be realized from conventional material to negative index material due to quantum coherence in our scheme.