测试技术学报2025，Vol.39Issue(2)：155-163,9.DOI:10.62756/csjs.1671-7449.2025021
一种基于遗传算法的单弹光调制高速椭偏技术
A High Speed Ellipsometry Technology for Single Photoelastic Modulation Based on Genetic Algorithm
摘要
Abstract
A high-speed single photoelastic modulation(PEM)ellipsometry measurement method based on polarization modulation of PEM and parameter extraction of single modulation period genetic algorithm is proposed to address the issues of phase locking multiple period signals and inability to quickly obtain sample optical ellipsometric parameters and thin film thickness in single PEM measurement technology.The time resolution of this method can reach up to μs level.To ensure the accuracy and stability of the algorithm,the phase delay amplitude(δpeak)of the PEM system is calibrated by the extremum of the interference signal within a modulation period of the system and the optical ellipsometry parameter range of the sample is determined.This calibration method can significantly shorten the calculation time and improve the calculation accuracy.By measuring the air and samples(made of silicon dioxide coated on silicon with thicknesses of 60 nm and 100 nm),the experiment shows that the static phase delay(δstatic)of the PEM system fluctuates stably within the measurement range.The maximum deviation of δstatic is 0.007 3 rad,and the standard deviation is 0.003 3 rad.The linear fitting coefficient R2 of the duty cycle between δpeak and FPGA output signals is 0.999 5.The experiments show that the relative error between the measured thickness of the sample film and its true value is less than 0.1%and the deviation is within 1 nm.The required modulation signal time for ellipsometric parameter measurement is 8.3 μs,which is 1～2 orders of magnitude faster than traditional PEM phase-locked ellipsometry methods.The results show that the high-speed single PEM ellipsometry mea-surement technology achieved by this method has high accuracy and stability,and lays the foundation for subsequent research on high-speed multi-PEM ellipsometry technology.关键词
高速椭偏测量/弹光调制/遗传算法/图像拟合仿真Key words
high-speed ellipsometry measurement/photoelastic modulation/genetic algorithm/image fitting simulation分类
计算机与自动化引用本文复制引用
徐承雨,张瑞,薛鹏,郭浩杰,王赛飞,吕健宁,武振涛,王志斌..一种基于遗传算法的单弹光调制高速椭偏技术[J].测试技术学报,2025,39(2):155-163,9.基金项目
国家自然科学基金资助项目(62105302) （62105302）
