Laser Doppler Vibrometer Without Directional Ambiguity Using Rectangular Phase Grating  

使用矩形相位光栅的可辨向激光多普勒测振仪

作　　者：邓罗根[1] 刘巽亮[1] 李绍英 

机构地区：[1]北京理工大学工程光学系,北京100081

出　　处：《Journal of Beijing Institute of Technology》1993年第1期49-61,共13页北京理工大学学报（英文版）

摘　　要：The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scattered laser Doppler vibrometer without directional ambiguity using the single peri- od rectangular phase grating as the beam-combiner described.The principles of this kind of vibrometer are explained in detail,and some experimental re- sults are given.In this kind of vibrometer,the rectangular phase grating, without the zero diffracted order and even orders,is used to eliminate use- less stray light and to combine the useful signal light.Differential electronics is employed to reject signal noise.Therefore,the signal-to-noise ratio of Doppler signals and the measurement accuracy of the instrument are im- proved and the range of application is expanded.讨论了激光多普勒技术的双相检测辨向方法,分析了单周期矩形相位光栅的衍射效率,在此基础上,描述了一种利用双相检测法辨向的、以单周期矩形相位光栅作合束器(beam-combiner)的后向散射型激光多普勒测振仪,详细说明了仪器的工作原理,给出了有关的实验结果.采用能消除零级衍射光的矩形相位光栅来抑制杂散光和结合微弱的信号光,同时还在信号处理中采用差动电路来消除噪声,所以该仪器能在目标散射光比较微弱的情况下获得高信噪比(SNR)的信号,从而有利于扩大应用范围和提高测量精度.

关 键 词：laser vibrometers ANEMOMETERS laser Doppler technique/rectangular phase grating two-phase detection directional discrimination 

分 类 号：TH741[机械工程—光学工程]