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一、前言利用激光多普勒效应进行气体液体和固体的速度测量,已在国内外得到广泛的重视和研究,并已将此新技术用于科研和生产。但是,通过测量激光的多普勒频移值△f,来求运动体的速度,其测速精度将受激光波长、接收方向及双光束夹角等换算因子精度的影响。衍射光栅多普勒频移信号△f,可由双光栅干涉系统产生,它所得到的多普勒信号和入射光的方向及光波波长均没有关系,只决定于光栅常数和光栅的运动速度。通过分偏振移相,还能得到四个90°相移的干涉信号,可直接用计数示波器和李沙育图形测量光栅的运动速度。因此,利用衍射光栅测量运动物体的速度
I. Introduction The speed measurement of gas liquids and solids using laser Doppler effect has gained widespread attention and research both at home and abroad and has been used for research and production. However, by measuring the laser Doppler frequency shift △ f, to find the speed of the moving body, the speed accuracy will be affected by the laser wavelength, the receiving direction and the angle of the double beam conversion factor accuracy. The diffraction grating Doppler shift signal △ f can be generated by the double grating interference system. The Doppler signal it obtains has no relation with the direction of the incident light and the wavelength of the light, but only depends on the grating constant and the moving speed of the grating. By dividing the polarization phase shift, but also to get four 90 ° phase shift of the interference signal can be directly measured with a counting oscilloscope and Li Shayu grating moving speed. Therefore, the diffraction grating is used to measure the velocity of moving objects