门镜

门镜 (又名猫眼 )是家用防盗门上常用的一种光学器件 .其整个装置的直径不足2ｃｍ ,长度约为 4ｃｍ .通过门镜 ,室内人可以清楚地看到门外来访者的形象 ,而从门外却看不到里面的景物 .这是怎么回事呢 ?拆开门镜 ,能看到固定在一金属管中的三个直径不足 1ｃｍ的镜片 ,其中两个镜     

非线性物理简介:8.光学孤子及其在光纤通讯中的应用

本文介绍了光学孤子的形成、特性及其在光纤通讯中的应用．     

人工智能,神经网络与光学

从发展智能计算机的战略出发，介绍了人工神经网络的研究背景和发展简史，扼要说明了神经元的基本运算功能以及人工神经网络的构造和类型。从可学习性，大规模并行性以及联想和容错能力等方面，通过已有研究成果的实例，分析了人工神经网络作为一种新型智能信息处理系统所具有的主要特点。并从硬件实现的角度，阐明了人工神经网络与光学或光子技术的密切关系。     

A Powerful Simple Shooting Method for Designing Multi-Pumped Fibre Raman Amplifiers

A simple shooting method dedicated to the design of multipump discrete Raman fibre amplifiers (RFAs) ispro posed and discussed in detail. A novel scheme to provide a good initial guess for backward lightwaves is also proposed to improve the efficiency and robustness of the method. Using the proposed method, a discrete RFA with four backward pumps and 93 signal channels is simulated for the maximum number of interaction waves considered simultaneously in the RFA design reported previously; to our best knowledge. The numerical simulation results show that the proposed method is fast and robust. It can be used in the design of RFAs with various configurations including co-, counter- and bi-directJonal-pump schemes to provide an actual modelling.     

Self-Mixing Interference in Dual-Polarization Microchip Nd：YAG Lasers

The self-mixing interference in dual-polarization microchip Nd: YA G lasers is demonstrated. Under optical feedback, the orthogonal polarization components of the laser would undergo antiphase intensity modulations; at high feedback level, the polarization switching appears. We also observe that the laser self-mixing sensitivity changes periodically with the frequency difference of orthogonal polarizations. An initial theoretical model is put out and agrees well with the experiments. The results are useful for self-mixing sensitivity enhancement and offer a new way of absolute distance measurement.     

反常色散区高阶色散对啁啾演变的影响

在单模光纤反常色散区，首次推出了带有初始啁啾的高斯脉冲在二阶，三阶速度色散效作用产生的啁啾解析表达式，用数值法模拟了光纤中啁啾演变过程，研究结果表明，二阶，三阶色散导致非线性啁啾，三阶色散只在脉冲沿附产生啁啾极值，从而使脉冲在前后沿产生振荡结构，当具有负初始啁呼的高斯脉冲入射时，在脉冲中心小区域内净啁啾等于零，可形成孤子。     

多光束相干控制光学跃迁的理论研究

根据量子干涉的基本原理，研究了在多束相干激光场作用下分子或凝聚态体系光学跃迁几率与光场的相位关系，推导了作为相干控制基础的多路径光学跃迁的一般模型及其特殊情形的跃迁几率的关系表达式，归纳了已有的相干控制激发方案，提出的频域的相干控制可用统一的量子理论描述，理论研究的结果表明，对多路径量子跃迁过程，在相干外场的作用下，会引起态的量子干涉，使总跃迁几率的大小随外场的相位变化而改变，这是实现与光学跃迁过     

飞秒激光脉冲在三能级有机分子介质中传播时的频谱分析

通过采用预估校正的时域有限差分法求解麦克斯韦-布洛赫方程,我们研究了飞秒激光脉冲在三能级有机分子(4,4-二甲氨基二苯乙烯分子)介质中传播时脉冲的频谱演化情况.在单光子共振情况下,即入射脉冲频率等于1、2能级之间的共振频率,对大面积入射脉冲,由于强的二次激发的作用,电场频谱中出现了在ω32附近振荡的频率成分,ω32是2、3能级之间的共振频率,说明对大面积入射脉冲二能级模型已经失效,需要采用多能级模型来描述分子介质.在双光子共振情况下,即入射脉冲频率等于1、3能级之间的共振频率的一半,由于介质中放大的自发辐射和四波混频的作用,部分入射脉冲能量转化为高频和低频电场成分的能量,分子介质表现出了很强的光功率限幅特性.     

激光致晶态Ag11In12Te26Sb51相变介质光学常量的研究

研究了结晶度对Ag11In12Te26Sb51相变薄膜光学常数的影响。用初始化仪使相变薄膜晶化，改变晶化参量得到不同的结晶度，当转速固定时，随激光功率的增加，折射率基本随之减小，消光系数先是增大，而后减小；当激光功率固定时，随转速的增大，折射率也随之增大，消光系数也是先增大后减小。非晶态与晶态间的变换、薄膜微结构的变化（包括晶型的转变和原子间键合状态的变化）以及薄膜内残余应力的影响Ag11In12Te26Sb51相变薄膜复数折射率的主要原因。测量了单层膜的透过率和CD－RW相变光盘中Ag11In12Te26Sb51薄膜非晶态和晶态的反射率。     

Design and Fabrication of 1.06 μm Resonant-Cavity Enhanced Reflective Modulator with GaInAs/GaAs Quantum Wells

A resonant-cavity enhanced reflective optical modulator is designed and fabricated, with three groups of three highly strained InGaAs/GaAs quantum wells in the cavity, for low voltage and high contrast ratio operation. The quantum wells are positioned in antinodes of the optical standing wave. The modulator is grown in a single growth step in an molecular beam epitaxy system, using GaAs/AlAs distributed Bragg reflectors as both the top and bottom mirrors. Results show that the reflection device has a modulation extinction of 3 dB at -4.5 V bias.