无频响影响的光弹调制器定标新方法  

New Calibration Method for Photoelastic Modulator WithoutFrequency Response

作　　者：杨军营 韩培高 魏莹莹 Yang Junying;Han Peigao;Wei Yingying(School of Physics and Engineering,Qufu Normal University,Qufu 273165,Shandong,China;Shandong Province Key Laboratory of Laser Polarization and Information Technology,Qufu 273165,Shandong,China)

机构地区：[1]曲阜师范大学物理工程学院,山东曲阜273165 [2]山东省激光偏光与信息技术重点实验室,山东曲阜273165

出　　处：《中国激光》2024年第8期119-125,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(11104160)。

摘　　要：针对现有光弹调制器定标方法受探测器频率响应的局限性,提出一种新的光弹调制器相位调制幅值(Am)定标方法。利用起偏器、光弹调制器、波片,以及检偏器构建定标光路,利用Am=5.136 rad的二次谐波分量零值点作为定标辅助点,将待定标点与定标辅助点间的一阶贝塞尔函数比值作为定标函数,通过测量待定标点与定标辅助点的一次谐波分量比值反推出待定标点的真实相位延迟量幅值。该方法排除了由探测系统频率响应特性带来的定标偏差,并且可以对光弹调制器整个工作区间的相位延迟量幅值进行定标。该方法操作简单、系统鲁棒性强、定标范围广。Objective With the wide application of ellipsometry spectroscopy technology as the core device for ellipsometry spectrometers in recent years,an increasing number of researchers have begun to study photoelastic modulators(PEM).The amplitude of the phase delay generated when the PEM performs phase modulation is influenced by the control voltage,temperature,and other factors;therefore,the PEM must perform calibration before carrying out the work.Current calibration methods for the PEM mainly include the Bessel function ratio,half-wave flat-top,and fundamental frequency component maximum methods.Many calibration methods require the use of the Bessel function ratio,and the frequency response of the calibration system must be considered based on the ratio between different frequency octaves,which is also a problem likely to be ignored.Moreover,this problem is difficult to solve.To solve this problem,we propose a new calibration method that can eliminate the influence of the frequency response of the calibration system.The proposed method exhibits excellent system robustness.Methods The proposed system consisted of a calibration optical route polarizer,PEM,waveplate,and analyzer.This method has no special requirements for the azimuths of the polarizer,analyzer,waveplate,or the phase delay of the waveplate in the system.In this method,the zero-point of the second-harmonic component,Am=5.136 rad,was used as the calibration auxiliary point,and the ratio of the first-order Bessel function between the undetermined and calibration auxiliary points was used as the calibration function.By determining the ratio of the first harmonic component between the fixed and calibration auxiliary points,the real-phase delay amplitude of the undetermined point was derived via calculations.Results and Discussions The proposed method uses the ratio of the Bessel function of the same order between different values instead of the ratio between different frequencies,which solves the frequency-response problem of the calibration system.The calib

关 键 词：光弹调制器 定标 贝塞尔函数 峰值延迟量 

分 类 号：O439[机械工程—光学工程]