Research On The Advanced Parameters Problem Of Mueller Matrix Ellipsometry System

Mueller matrix ellipsometer(MME)has been widely used in optoelectronic devices,flat panel display,photovoltaic solar cells,quantum optics,optical communication and biomedical science and technology.As the size of measurement sample becomes smaller and smaller and the measurement structure becomes more and more complex in these emerging fields,the accuracy requirement of MME becomes higher and higher.Among all kinds of MME structures,the dual rotating-compensator Mueller matrix ellipsometry system(DRC-MME)has a wider application prospect because of its wide bandwidth and high accuracy.The key to realize high-precision measurement of DRC-MME is how to describe the non-ideal factors of the system and calibrate them accurately.For this reason,this paper introduces the concept of advanced parameters to analyze the non-ideal factors of the system,and conducts in-depth research on advanced parameters of DRC-MME.The main purpose of this study is analyzing the influence of these advanced parameters on measurement accuracy of DRC-MME,and designing methods to calibrate these advanced parameters.Based on this purpose,the main research work and innovations of this paper include the following parts:Firstly,the basic principle of DRC-MME is analyzed and studied.On this basis,the non-ideal factors of each element in DRC-MME are analyzed,and the advanced parameters model of each element,the polarization correlation correction model of light source and spectrometer are established.Then the advanced parameters model of DRC-MME is established by combining the system depolarization correction model.In order to improve the robustness of DRC-MME,based on the established advanced parameters model of DRC-MME,the optimal allocation of the basic parameters of the system is analyzed.Secondly,the error propagation model of the advanced parameters describing the non-ideal factors of the system is established,as well as the random error propagation model.Based on the error propagation model of advanced parameters,the error tolerance of some advanced parameters required for given measurement accuracy is analyzed.The correctness of the derivation of the system parameter error propagation model is verified by numerical simulation,and the error tolerance of all system parameters is given.This work provides guidance for the calibration of system parameters.Thirdly,before calibrating the parameters of DRC-MME,the polarization correlation coefficients of light source and spectrometer in the system need to be measured.In this paper,a method for simultaneously measuring the polarization correlation coefficients of light sources and spectrographs without resorting to additional broadband light sources or spectrographs with known polarization characteristics is proposed.An experimental measurement system is designed to measure the polarization correlation coefficients of the optical source subsystem and the spectrometer subsystem in DRC-MME.The correctness of this measurement method is also verified.Fourthly,the process and main problems of advanced parameter calibration are analyzed,and a new advanced parameters model of focusing lens is established to clarify the correlation between its parameters.In order to calibrate the equivalent advanced parameters of the inner slice,a method of using anisotropic crystal substrate to calibrate the advanced parameters of the focusing lens is proposed,and the correctness of the method is verified by numerical simulation.Finally,the accuracy of advanced parameter model of DRC-MME and its calibration method is verified by experiments,and the calibration fitting results of different system models of DRC-MME are compared and analyzed.It is shown that the advanced parameter model of DRC-MME and calibration of its parameters effectively improves the accuracy of DRC-MME.In summary,this paper focuses on the research of advanced parameters of DRC-MME,and deeply studies and analyses the theoretical modeling,error transfer analysis and parameter calibration of advanced parameters of DRC-MME,and puts forward corresponding solutions.These research results are expected to further enrich the basic theory of the development of high-precision Muller matrix ellipsometer and the measurement of optical precision instruments in China,and improve the overall level of high-precision optical measurement theory,methods and technology in China.