单缝衍射法测量散射粒子运动速度

Measurement of the Velocity of Scattering Particles with Single-slit Diffraction

文章提出了一种利用单缝衍射来测量散射粒子运动速度的新方法,并设计了可行的光学系统和探测装置。该方法利用He-Ne激光器和单只光电探测器并配合简单的光学发射和接收系统实现了对散射粒子一维速度分量的测量。实验结果表明,此方法可以对大区域内的目标散射体进行非接触式主动测速,测速精度可达10-2mm/s。与经典的激光多普勒测速方法相比,它具有测量区域大,目标捕捉容易,测试系统简单,方便调节以及测速范围连续可调等优点。此外,此方法对激光器的频率稳定性、光电探测器的频带宽度和散射粒子尺寸大小的要求都比较低。

This paper proposes a new method for measuring the velocity of scattering particles with the theory of single-slit diffraction, and designs a feasible optical system and detection equipment for the method. The method adopts a He-Ne laser and a single photoelectric detector, combined with simple optical transmission and receiving system, to implement the measurement of one-dimensional velocity component of scattering particles. The velocity of scattering particles can be measured actively in a wide area without touching the scattering objects. The measurement accuracy can achieve 10-2mm/s. Compared with the classical laser Doppler velocimetry, this method has many advantages： wide measuring area; easy to catch object; convenient to adjust; and continuously adjustable velocity measuring range. In addition, the system has less demand for laser＇s frequency stability, photoelectric detector＇s frequency width and scattering particles＇ size.