同步移相干涉的测量性能

Measurement Performance of Simultaneous Phase-Shifting Interferometer

详细分析了一种基于二维正交光栅衍射的同步移相干涉测量系统的组成结构,包括干涉系统、空间分光部件、偏振移相部件以及图像采集与处理系统。选择了二维正交透射光栅的四个衍射级次的光束作为测试光,理论和实验都证明这种方案具有良好的分光效果;用偏振方向依次改变45°的四片偏振片构成偏振阵列作为移相器件,并根据空间一致性要求,分割得到依次具有90°移相的四幅独立干涉图,获得了较高的移相精度;在幅频积低于100 Hzλ的振动环境中,系统测量重复性的峰谷值优于0.02λ,可以用于一般的在线检测和动态测量。

The structure of a simultaneous phase-shifting interferometry system based on two-dimensional （2D） orthogonal grating diffraction is analyzed in detail, including components of interference, spatial beam splitting, polarizing phase-shifting element, and image sampling and processing. The four diffraction-order beams of the 2D orthogonal transmission grating are taken as the testing beams. Both the theory and the experiment show that the beam splitting of the system function well. A polarizing array, consists of four linear polarizing elements of which transmitting directions change 45° in turn, acts as the phase-shifter. According to the requirement of spatial consistency, the four independent interferograms with 90° phase shift are divided. High phase-shifting precision is obtained. The repetitive experimental results show that, when the amplitude-frequency product of environmental vibration does not exceed 100 Hzλ, the peak to valley of testing repeatability is less than 0.02λ, so the advanced system can be used in on-line testing and dynamic measurement.