基于二维光栅分光的同步移相干涉测量技术

为了干涉测量的抗振目的,提出了一种新的同步移相干涉测量方案并搭建了实验装置。整个测量系统在迈克耳孙偏振移相干涉仪的基础上,利用一个正交的二维光栅产生对称分光,选取对于理想光栅衍射效率一致的(±1,±1)级衍射光作为测量分光路,使之分别通过偏振方向依次相差45°的一个偏振片组,从而分别形成0°、90°、180°和270°相移的四幅移相干涉图,按照传统的四步移相算法,对被测波面进行了复原。分析了光强畸变和移相误差对系统的测量误差的影响。利用该系统测量一球面系统,结果与在ZYGO干涉仪上相比较,球面系统的均方根误差相差0.012λ,峰谷值相差0.051λ。

Simultaneous Phase-Shifting Interferometry Based on Two-Dimension Grating

For the anti-vibration in interferometry, a new simultaneous phase-shifting method based on Michelson polarization phase-shifting technique, is presented. In the corresponding set-up, a 2-dimentional grating is used. Through the grating, 4 diffracted beams of (±1,±1) orders are formed for the same diffracting efficiency. Let each beam pass one of four polarizing plates, of which polarization directions differ in turn by 45°. So four interferograms which have 90° phase-shifting interval are obtained simultaneously. By using the 4-bucket algorithm, the wavefront of the test piece is derived. The intensity disuniform and phase shift error are analyzed. A spherical system of a sort is tested by the advanced system and ZYGO interferometer repectively. The results show that the difference of root-mean-square and peak to valley in the two experiments are 0.012λ and 0.051λ respectively.