高反射腔镜双折射效应对腔增强光谱技术的影响  

Birefringence effect of high reflectivity cavity mirrors and its influence on cavity enhanced spectroscopy

作　　者：刘建鑫 赵刚[1,2] 周月婷 周晓彬 马维光 Liu Jian-Xin;Zhao Gang;Zhou Yue-Ting;Zhou Xiao-Bin;Ma Wei-Guang(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Laser Spectroscopy,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学激光光谱研究所,量子光学与光量子器件国家重点实验室,太原030006 [2]山西大学极端光学协同创新中心,太原030006

出　　处：《物理学报》2022年第8期124-129,共6页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFA0304203);国家自然科学基金(批准号:61875107,61905136,61905134,62175139);山西省高等学校科技创新项目(批准号:2019L0062)资助的课题~~。

摘　　要：在吸收光谱技术中,使用光学腔增长激光与气体介质的作用路径,可提升探测灵敏度.然而,高反射率腔镜会存在双折射效应,导致光学腔产生两个本征偏振态,入射光在两个偏振方向相移的不同会导致腔模的分裂,会引起腔增强光谱信号以及腔衰荡光谱信号的扭曲.本文观测到了双折射效应下腔增强信号的频率分裂现象,并给出了函数模型,拟合结果表明其可以准确得到透射腔模中不同偏振光的比例.根据上述比例,可给出考虑不同耦合效率、双折射效应下的腔衰荡信号模型,实验结果表明相较于传统e指数模型,本文模型可更精确描述腔衰荡信号,得到拟合残差的标准偏差最大抑制了9倍.该分析有利于改善腔衰荡信号信噪比和不确定性,提升其浓度反演准确度.In laser absorption spectroscopy,in order to improve gas detection sensitivity,optical cavity with high finesse is used to prolong the interaction path between the laser and the absorber.However,the birefringence of high reflectivity cavity mirrors generates two polarization eigenstates,and owing to the different phase shifts along the two directions,the cavity mode will be split.In this work,we first measure the cavity enhanced signal under birefringence and observe the mode split.And a model to mimic cavity enhanced spectroscopy under birefringent effect is presented,which can accurately fit the different polarization ratios at transmission.Finally,we propose a cavity ring-down signal model considering different coupling efficiencies of the two polarization directions of the cavity.Comparing with the conventional exponential model,the standard deviation of residual maximum suppression is as high as 9 times.And this analysis is helpful in improving the signal-to-noise ratio and uncertainty of cavity ring-down signal and increasing the accuracy of concentration inversion.

关 键 词：Fabry-Pérot腔 双折射 腔衰荡光谱 

分 类 号：O433[机械工程—光学工程]