基于耦合双振子模型的手性分子的超极化率

本文从手性分子的耦合双振子经典模型出发,推导出手性分子的超极化率.在特定情况下,给出了三阶非线性极化率的表达式.基于该模型讨论了手性介质分子各向同性分布的宏观非线性极化率.     

RELATIONSHIP BETWEEN INTENSITY OF SURFACE SECOND HARMONIC GENERATION AND MOLECULAR STRUCTURE IN HELIX MOLECULAR FILMS

The relationship between intensity of surface Second Harmonic Generation (SHG) and the pitch, radius and azimuthal angle of molecules on the surface of helix molecular films is analyzed. The values of pitch and radius corresponding to the maximal intensity of SHG have been shown to exist. The theoretical results are compared with the experimental ones reported by M?hlman et al., and the limitation of their conclusion is also pointed out.     

大学物理课程考试方法改革与实践

大学物理课程兼有传授科学知识和科学素质培养的双重作用,相应的课程改革一直在进行,而与之紧密相连的考试方法改革也应该进行.为了能够更全面客观地考核学生的学习效果,在累加式考试的基础上增大了平时测试的比例,进行随堂测试、演示实验分析、研究性作业.实践表明这种考试改革取得了良好的效果.     

文科物理教学方法改革尝试与思考

本文从我校多年的教学实践与教学改革所进行的一些尝试中,重新思考了有关文科物理课程的教学内容、教学方法、教学手段以及考核方式.并从文科学生对待物理学的心理、学习物理的态度上分析了目前在美国、中国台湾地区以及一些欧洲国家的大学盛行的一种新的教学模式——工作室物理,应用于文科物理教学的可能性和必要性.     

手性分子介质非线性光学研究新进展

文章介绍了近年来手性分子介质及材料的非线性光学性质的研究状况，综述了手性分子非线性微观模型的使用情况，给出了一些典型的二阶、三阶非线性光学实验结果，用这些微观模型可以正确地分析这些结果．同时指出了未来研究的趋势，及研究成果可能应用的领域．     

Optical bistability in tunable fiber laser using fiber Mach-Zehnder interferometer

In this letter, a novel mechanism of hybrid optical bistability is proposed by using nonlinear mechanism in the frequency domain. This device is based on electro-optical feedback through the fiber Bragg grating on piezoelectric transducer (PZT) to tune continuous wave (CW) fiber laser. The optical bistable characteristics for two manners of separately alternating input power and bias voltage are discussed. The smallest wavelength shift of the order of 0.001 nm needed to realize a switching process in this optical bistability device is estimated. The potential applications of this device in the optical fiber sensor technique are also discussed.     

A Novel All-Optical Switch in a Double-Loop Sagnac Ring Coupled with a Nonlinear Ring Resonator

We propose a novel configuration of all-optical switch based on a double-loop Sagnac ring coupled with a nonlinear ring resonator. In the case of self-phase modulation, the reducing switching threshold power clown to mW is predicted, which is the improvement of earlier works on all-optical switches. The switch optimization is analysed.A way to increase the response speed of all-optical switches is suggested.     

Optical Bistability by Using a Tunable Fibre Laser with Fibre Fabry-Perot

We observe a novel hybrid optical bistability by using an electro-optically tuned cw fibre laser with a fibre FabryPerot filter. The principles of the optical bistable device in two operation manners are analysed. The applications in monitoring the wavelength shift of a tunable fibre laser and fibre sensor of digital type are also discussed.     

成像激光雷达中的扫描方案

文中对成像激光雷达系统中的几种扫描方式－光栅扫描，声光扫描，电光扫描和光机扫描进行了分析、比较，给出了一种适合于低空飞行前视避障系统的二维摆镜扫描设计方案，具有结构紧凑，体积小等特点，并且可通过计算机来控制摆动的转轴，实现预定的扫描方案，为实现激光雷达系统小型化提供了重要方案。