Error and Compensation of Non-polarization Splitting Prism(NPBS) in Single Frequency Laser Interferometer

摘要

An online compensation method of non-polarization splitting prism(NPBS) error in single frequency laser interferometer is presented in the paper. We study the effect of incident conditions to polarization characteristics of NPBS, establish online performance detecting system to study the effect of polarization error of NPBS in single frequency laser interferometer, realize the online compensation of NPBS additional phase shift by adding a half-wave plate to optical path, which improves contrast ratio of interference signal and restrains nonlinear errors of single frequency laser interferometer.The method proposed in our paper has an obvious advantage compared with the method of adjusting a quarter-wave plate to compensate additional phase shift of NPBS. The results indicate that the method can effectively compensate polarization error of NPBS, improve the quality of interference signal and raise measurement resolution of interferometer. Therefore, the method can be widely used in many fields such as the investigation and preparation of nanometer high-precision laser interferometer.