共光路径向剪切干涉仪的设计

摘要

针对常规像移式干涉仪无法用于大口径、长光路光学系统波像差检测的工程问题,设计了共光路径向剪切干涉仪以消除采用标准波面所引入的系统误差.设计中采用由三角棱镜与斜方棱镜组合而成的胶合棱镜组作为波面剪切器件,将待测波面与其复制波面产生干涉,并通过一组有不同相对孔径的透镜切换装置来控制干涉仪剪切比.与4D动态干涉仪在不同条件下的比对试验数据表明,设计的剪切干涉仪的测试重复精度约为λ/80,实际测试精度RMS优于λ/20(λ=630 nm).这种设计极大地缩小了仪器外形尺寸与重量,提高了超长光路干涉检测的效率.%As conventional phase shifting interferometers can not test the wavefront aberration from a large diameter and long optical path system accuracely, a new commonpath shearing interferometer is designed to elimnate the system error introduced by the standard wavefront. The new design takes an agglutination prism consisting of a triangular prism and a rhombic prism as a shear device to produce interference by the wavefront under-test with its replication. A group of different relative aperture lens switching devices are used to control the shearing ratio of the shearing interferometer. Compared with the data from 4D dynamic interferometers under different temperature conditions,it shows that the repeatability of designed shearing interferometer is about λ/80 and the accuracy of root mean square is better than λ/80(λ= 630 nm). The design of the commonpath shearing interferometer greatly reduces its dimension and weight and also improves the experiment efficiency for long optical path interference measurement.