可调谐液晶双折射滤光器的原位定标方法(特邀)  

In Situ Calibration of the Tunable Liquid-crystal Birefringent Filter(Invited)

作　　者：侯俊峰[1,2] 孙英姿 林佳本[1,2] 张洋[1] 王东光 邓元勇[1,2] 张志勇[1,2] HOU Junfeng;SUN Yingzi;LIN Jiaben;ZHANG Yang;WANG Dongguang;DENG Yuanyong;ZHANG Zhiyong(National Astronomical Observatories of Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,School of Astronomy and Space Science,Beijing 100049,China)

机构地区：[1]中国科学院国家天文台,北京100101 [2]中国科学院大学天文与空间科学学院,北京100049

出　　处：《光子学报》2023年第5期94-103,共10页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.11773040,11427901);中国科学院空间科学战略性先导科技专项(Nos.XDA15010800,XDA15320102);中国科学院青年创新促进会(No.2022057);国家重点研究发展计划(No.2021YFA1600500)。

摘　　要：为了降低向列液晶调制器的相位延迟漂移影响以提高可调谐液晶双折射滤光器的透过轮廓和谱线定位精度,提出了一种基于傅里叶分析的非线性拟合原位定标方法。该方法从偏振干涉理论出发,利用傅里叶分析获得双折射滤光器每一级的相位偏移量;然后建立相位偏移量与向列液晶调制器相位延迟漂移量的函数模型,最终采用非线性拟合法获得相位延迟漂移量,从而实现双折射滤光器的原位定标。误差分析和实验研究表明,该方法对滤光器的晶体参数以及前置滤光片的误差依赖较弱;测量方法简单便捷,一次测量即可完成定标;相位延迟漂移量的定标精度优于5°,对应双折射滤光器(带宽0.01 nm)的线心漂移量小于0.0003 nm。The sun is a huge plasma laboratory,in which all phenomena and processes are caused by electromagnetic interaction.Therefore,the observation and research of the solar magnetic field play an important role in solar physics and space weather science.At present,the measurement of solar magnetic field is mainly based on the Zeeman effect and its polarization variation in a narrowband spectrum.Therefore,for imaging equipment,the solar magnetic field measurement requires a filter with a bandwidth of about 0.01 nm.High precision and high sensitivity tunable narrowband imaging is one of the core technologies for solar telescopes to achieve accurate magnetic field observation.Lyot birefringent filter is an imaging filter invented by Lyot Bernard in 1933.It realizes ultra-narrow band filtering through the interference effect of high birefringent crystals,and is the most commonly used narrow band imaging device for solar telescopes.Traditional birefringent filters use rotating wave plates to adjust the central wavelength of transmission.However,mechanical modulation is not only slow,but also faces reliability risks such as life,bubbles,and oil leakage when applied to space telescopes.Based on this,with the rapid development of liquid crystal modulation technology in recent years,tunable liquid crystal birefringent filters are gradually favored.Instead of mechanical modulation,Liquid Crystal Variable Retarder(LCVR)is used to achieve wavelength adjustment through transmission,which is fast and free of risks such as bubbles and oil leakage,significantly improving the scientific performance and reliability of the filter.However,since LCVR is a liquid crystal electro-optic modulator,when tunable liquid crystal birefringent filters are applied to space telescopes,the retardation-voltage curve of LCVR may drift due to the combined effects of radiation,force,heat,charging and other factors,which may lead to divergence of the transmission profile of the filter and the drift of the central wavelength,thus reducing the measurement acc

关 键 词：太阳望远镜 双折射滤光器 向列液晶调制器 相位延迟 原位定标 

分 类 号：P111[天文地球—天文学]