| With the development of optical technology,the application of polarization measurement technology has become more and more extensive,such as optical device detection,medical diagnosis and biomedicine and other fields.Among them,the spectral encoding Mueller matrix measurement technology has the advantages of single optical path detection and the detection speed is only limited by the light source,so it has great application value in miniaturization and rapid polarization measurement.The phase retarder is the core component of the spectral encoding Mueller matrix measurement system.In the actual processing process,the processing error of the phase retarder is unavoidable,resulting in an error in the amount of phase retardation.Therefore,the calibration of the phase retardation of the phase retarder is very important for accurately measuring the Mueller matrix elements of the sample.The traditional calibration method needs to use two kinds of definite samples.The different samples have inconsistent initial phases,so the phase delay error calibration will be inaccurate,which will affect the measurement accuracy of the Mueller matrix.In this paper,firstly,by simulating the solution process of the Mueller matrix under ideal conditions,the value of the sample Mueller matrix without error is obtained,and the feasibility of using Fourier coefficients to solve the target Mueller matrix method is verified.Two factors that affect the measurement accuracy and stability of the Mueller matrix are summarized: the azimuth error and the phase delay error.And the impact of these two errors on the Mueller matrix measurement system is analyzed in detail.The simulation results can be obtained : the phase delay error is the main influencing factor.When the phase delay error is only 0.5rad,the measurement root mean square error of the air Mueller matrix is greater than 0.4;Secondly,an error transfer model with phase delay error is obtained through theoretical deduction.The polarizer method and the waveplate method are proposed to calculate the phase retardation error,which effectively solves the problem of inconsistent initial phase error caused by different samples in the traditional method;Finally,based on theoretical simulation,built the spectral encoding Mueller matrix measurement error calibration system device and calculates the phase retardation error calculated by the two methods.The phase retardation error calculated by the polarizer method is used for compensation,and the average measurement error does not exceed 0.04,and the maximum measurement error does not exceed 0.07.The phase retardation error calculated by the waveplate method is used for compensation,the average measurement error does not exceed 0.04,and the maximum measurement error does not exceed 0.08,which verifies the feasibility of the polarizer method and the wave plate method for calculating the phase retardation error.The polarizer method and waveplate method proposed in this paper to calibrate the phase delay error.There is no need to change the sample during the measurement process,which avoids the problem of inconsistent initial phase errors caused by error calibration of the traditional two samples.It is of great significance to the error analysis and compensation system of the spectral encoding Mueller matrix measurement,which is helpful to promote the application of this type of ellipsometer and the quantitative application of its polarization measurement data. |
