一种基于RGB三基色LED的白光光源

数字光源处理(DLP)投影技术是投影显示的一个重要分支,基于发光二极管(LED)照明技术的DLP投影显示技术则是目前DLP技术的一个重要发展方向。根据DLP投影显示技术的需要,对一种新型的LED混光光源进行了优化设计和仿真计算,得到了一种适合于为DLP微型投影机提供照明的LED混光光源。该混光光源可以提高LED光源的DLP微型投影机的光通量。     

光学频率标准与光钟的实现

综述了时间频率标准的发展过程.对构成光学频率标准的四个要素,即激光冷却、激光稳频、离子捕陷和光学频率梳进行了系统的介绍.详细描述了光钟的原理与系统构成,并对光学频率标准与光钟的应用前景进行了展望.     

Optical Feedback Characteristics in He-Ne Dual Frequency Lasers

Optical feedback characteristics in He-Ne dual frequency lasers are studied systematically in different feedback power ratios with a variable attenuator. Feedback power ratios vary from 0.010 up to 0.998. Five distinct regimes of self-interference effects are found and defined as regimes Ⅰ, Ⅱ,Ⅲ,Ⅳand Ⅴ. Accordingly, five optical feedback levels have been put forward in He-Ne dual frequency lasers. Strong mode competitions are observed in regimes Ⅲ and Ⅳ. In regime Ⅴ, multiple feedback effects are investigated. The basic theoretical analysis is also presented. Our results can advance the research of self-mixing interferometer and displacement sensor of He-Ne orthogonally polarized dual frequency lasers.     

纵模分裂式正交偏振双频He-Ne激光器

在激光器谐振腔中放入单轴石英晶体,由于石英晶体对o光和e光的折射率的不同,所以,在同一谐振腔中o光和e光有不同的光程和谐振频率.将其称之为模式分裂效应.利用这一效应可以制成频率达几十兆赫兹的双频激光器.针对原有理论与实验结果之间的某些差异,建立了一套分析该种类型双频激光器的理论.根据所建立的理论着重分析了谐振腔光轴与晶轴夹角α对激光器频差的影响.并绘出了He-Ne激光管L<150nm和150nm相似文献   

Laser self-mixing interference fibre sensor

Fibre sensors exhibit a number of advantages over other sensors such as high sensitivity, electric insulation, corrosion resistance, interference rejection and so on. And laser self-mixing interference can accurately detect the phase difference of feedback light. In this paper, a novel laser self-mixing interference fibre sensor that combines the advantages of fibre sensors with those of laser self-mixing interference is presented. Experimental configurations are set up to study the relationship between laser power output and phase of laser feedback light when the fibre trembles or when the fibre is stretched or pressed. The theoretical analysis of pressure sensors based on laser self-mixing interference is indicated to accord with the experimental results.     

A Novel Tunable Dual-frequency Laser with Large Frequency Difference

This paper proposed a novel tunable dual frequency laser with large frequency difference,which used LD to pump the Nd∶YAG microchip in the end surface and put the liquid pressure on the radial direction of the crystal by a pressure-transporting thin film. As a result of the stress birefringence, there was a mode splitting phenomenon of the microchip laser longitudinal mode. Both theoretical analysis and experiments indicated that there is a directly proportional relation between the frequency difference and the pressure, so the tunable frequency difference could be obtained when the pressure was changed. A large frequency difference of about 3.4 GHz with linear tunable relation was achieved in the experiment,so it can be a practical light source for the absolute distance interferometry.     

基于强度补偿式光纤传感器测金属线胀系数

分析了强度补偿式光纤位移传感器的补偿机理.通过测量定标,应用最小二乘法确定了该传感器的特性曲线和拟合方程.使用强度补偿式光纤传感器测量了黄铜和铝杆的线胀系数.实验结果表明:强度补偿式光纤位移传感器采用比值运算法给出测量结果,其灵敏度高,稳定性好,用其测量微小位移,可消除一些传统测量方法中待测参量较多而引入过多测量误差的问题,实现非接触测量,且克服反射式非补偿位移传感器因光源光强波动、光纤传输介质损耗及环境光干扰所带来的测量误差.     

A Novel Tunable Dual-frequency Laser with Large Frequency Difference

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腔调谐过程中激光器中两垂直偏振光的回馈特性

腔调谐过程中同时对HeNe激光器进行光回馈，设定回馈镜驱动信号的周期远小于腔调谐信号的周期，此时便获得腔调谐过程中谐振腔中两垂直偏振光的回馈信号. 回馈的形式分为仅垂直光回馈、仅平行光回馈以及两光同时回馈三种情况. 当两光同时回馈时，两模式间的模竞争较弱，两光回馈曲线有一定的相位差，该相位差小于180°，两光总体波动幅度变化趋势相反. 当仅单偏振光回馈时，两模式间的模竞争较强，两光回馈曲线始终反相，而且两光波动幅度变化趋势相同，此时可以将两光强度信号相减以实现成倍提高回馈信号幅度，从而提高系统灵敏度. 尤其仅垂直光回馈时，两光各自光强波动幅值都较大，并且在较大的增益曲线范围内保持光强波动幅值无明显变化，该特性可用于提高回馈系统的抗干扰能力，减少因激光功率漂移而引起的错误计数. 关键词： 自混合干涉 光回馈 模竞争 位移测量