衍射光栅外差干涉测量的研究

提出一种新的测量光栅运动的方法，它利用声光调制器产生两个频率的激光，将其中一个频率的光入射到光栅上，产生正负级衍射光，光栅的运动使衍射光实现多普频移，然后将衍射光与另一频率的光干涉，即可实现光栅运动的外差干涉测量，正负级衍射光的同时使可以消除光栅横移的影响。

Research on Diffraction Grating Heterodyne Interference Measurement

A new method of measurement of grating movement is proposed. Acoustical modulators are used to generate two laser beams with different frequency. One laser beam is project on to a grating. Positive and negative didffraction beams are produced by the grating. The movement of the grating causes the doppler frequency shift. Then the diffraction beam is interfered with the laser beam of another frequency to perform the heterodyne interference measurement of the grating movement. The utilization of positive and negative diffracting beams at same time can get ride of the influence of lateral movement.