Smeets G, George A
German-French Research Institute of Saint-Louis, 68 Saint-Louis, France.
Rev Sci Instrum. 1978 Nov;49(11):1589. doi: 10.1063/1.1135316.
A new species of laser Doppler velocimeter is presented based on wavelength detection with a two-beam interferometer. A finite optical path difference, Deltaphi, of the interferometer creates a sensitivity of the interference to wavelength changes. By means of a fast feedback system, the phase, Deltaphi/lambda is kept constant. Wavelength changes are immediately answered by changes of Deltaphi generated with a Pockels cell. The Pockels cell voltage represents a continuous signal proportional to the instantaneous velocity component of the scattering object. A time resolution of 1 micros or lower can be obtained. The field of applications includes velocity recordings in gas flows containing tracer particles as well as velocity recordings of moving surfaces. A number of experiments are described demonstrating the performance of the system.
提出了一种基于双光束干涉仪波长检测的新型激光多普勒测速仪。干涉仪的有限光程差Δφ使干涉对波长变化具有敏感性。借助快速反馈系统，相位Δφ/λ保持恒定。波长变化会立即通过普克尔盒产生的Δφ变化得到响应。普克尔盒电压代表一个与散射物体瞬时速度分量成比例的连续信号。可获得1微秒或更低的时间分辨率。应用领域包括对含有示踪粒子的气流中的速度记录以及对移动表面的速度记录。描述了一些实验以证明该系统的性能。
