显微液下云纹干涉测试系统

A Study of Microscopic Moire Interferometry in Liquid Medium

本文提出了一种具有超高灵敏度的显微液下云纹干涉法。首先使激光通过折射率ｎ＝１．６５７的液体，用氦氖激光即可获得２０８ｎｍ／条的位移场；其次，用高精度的晶体相移器配合微机图像采集和处理倍增技术，可获得５２ｎｍ／条的位移场，相当于１９２００线／ｍｍ的虚光栅，本系统光路简单。

A microscopic moire interferometry method with ultra high sensitivity was developed for in plane displacement measuring.By the method,the specimen grating was first immersed into a liquid refractive medium(α Bromonaphthalene with refractive index n=1.657) to increase the virtual grating frequency.In this stage sensitivity of 208nm/fringe was obtained.Then,fringe shifting multiplication technique was used to improve the efficacy and sensitivity of 52nm/fringe (which may give a moire of 19200 lines per mm) was finally achieved.The optical and mechanical arrangement for the method is relatively simple and easy to adjusy.