Interference effect on the liquid-crystal-based Stokes polarimeter  

作　　者：Jun-Feng Hou Dong-Guang Wang Yuan-Yong Deng Zhi-Yong Zhang Ying-Zi Sun 侯俊峰;王东光;邓元勇;张志勇;孙英姿(Key Laboratory of Solar Activity,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]Key Laboratory of Solar Activity,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [2]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 101408,China

出　　处：《Chinese Physics B》2020年第12期286-296,共11页中国物理B（英文版）

基　　金：Project supported by the Strategic Pioneer Program on Space Science,Chinese Academy of Sciences(Grant Nos.XDA15010800 and XDA15320102);the National Natural Science Foundation of China(Grant Nos.11427901,11773040,11403047,and 11427803)。

摘　　要：The Stokes polarimeter based on liquid crystal variable retarders(LCVRs)is envisaged as a promising novel technique for polarization measurement in space applications due to the inherent advantage of eliminating the need for conventional rotating polarizing optics and increasing the measuring speed.However,the intrinsic multi-beam interference in LCVRs limits its polarization accuracy by several percent.How to eliminate the influence of the interference effect becomes an urgent issue for the liquid-crystal-based Stokes polarimeter.The present study introduces a simplified but effective interference model based on the thin-film optics and polarized light theory to simulate the relationship between the interference effect of the LCVRs-based Stokes polarimeter and the polarization accuracy.The simulation results show that the transmittance variation of LCVR with the derived voltage is caused by multi beam interference between the indium tin oxide(ITO)film and the liquid crystal within LCVR,which produces a few percent of instrumental polarization.The instrumental polarization is about 0.01 and different for different wavelengths.An optimization method was proposed to reduce the instrumental polarization to 0.002,effectively improving the polarization sensitivity of the Stokes polarimeter limited by the interference.In addition,an experimental setup was built up to measure and analyze the influence of the interference effect of the LCVRs-based Stokes polarimeter on the polarization accuracy before and after the optimization.The experiment results are in good agreement with the simulation.

关 键 词：POLARIMETRY liquid crystal variable retarder(LCVR) interference effect 

分 类 号：O436.3[机械工程—光学工程] TH74[理学—光学]