马赫-曾德尔型相移矢量剪切干涉仪

为了实现对激光波面的等光程测试,设计了一个新颖的相移矢量剪切干涉仪。该干涉仪以马赫曾德尔结构为基础,为等光程干涉仪。通过在相干的两路光束中分别插入楔角方向正交放置的楔板实现矢量剪切;其中一块楔板分成两块(平板部分和楔板部分),楔板部分沿平板部分的表面移动,通过改变光程差来实现相移,2π相移所需的移动距离为几毫米的量级,该相移方法在相移精度控制上比较简单。文中还对楔板引入的横向剪切误差和相移误差进行了分析,最后给出了实验所得的一组相移干涉图。

Phase-Shifting Vectorial-Shearing Interferometer with Mach-Zehnder Configuration

A novel phase-shifting vectorial-shearing interferometer with a wedge plate phase-shifter is presented to measure the laser wavefront, which is common-path and based on Mach-Zehnder configuration. Vectorial shear (shearing in x and y directions simultaneously) in arbitrary direction is introduced by inserting two wedge plates orthogonally in two arms, respectively. One of wedge plates is split into two parts (parallel part and wedge part), and the phase shift is produced by moving the wedge part in contact along the parallel part, which results in the variation of the optical path difference. The moving distance for 2π phase shift is about several millimeters in a specific condition. Wedge plate phase-shifter increases the moving distance of PSI and makes the control of phase shift relatively easy. The lateral shear errors and phase shift errors induced by wedge plates are also discussed, and the experimental results of phase-shifting vectorial-shearing interference fringes are given.