High stability double Stokes-Mueller polarimetry under oblique incidence

Double Stokes-Mueller polarimetry (DSMP) has been applied to investigate the microstructure of non-centrosymmetric materials. Oblique incidence degrades measurement stability and consequently reduces accuracy, which has not been studied. This paper developed a high stability DSMP under oblique incidence using 3D rotation of polarization elements. The 3D Jones matrices of polarization elements are extended from their 2D counterparts. Then, the instrument matrix of DSMP under oblique incidence is established by converting 3D Jones matrices to Mueller matrices. The established instrument matrix is consistent with calculation and measurement conventions. Subsequently, the average condition number (CN), the range (R), and the standard deviation (SD) of CNs for the established instrument matrix are minimized by a genetic algorithm. Within pitch angle < 0.08π, the average CN, R, and SD are reduced by 50.72%, 97.15%, and 96.42%, respectively, compared to conventional DSMP. These results demonstrate high stability under oblique incidence. The framework for this work is extensible to linear polarimetry and nonlinear polarimetry, providing a general method to improve stability for enhanced sample observation and analysis.