Performance uniformity analysis of a wiregrid polarizer in imaging polarimetry

The polarimetric performance nonuniformity of a wire-grid polarizer (WGP) used in imaging polarimetry is investigated with a simple numerical model. The simulation results based on rigorous coupled-wave analysis show that the aperture ratio between the entrance pupil and the WGP significantly affects the uniformity among pixels of a WGP. Even with a WGP smaller than an imaging aperture, the results suggest that the design avoids incurring a Rayleigh anomaly, which causes a substantial increase in polarimetric nonuniformity. Minimizing the variation due to the characteristics of a WGP is important to reduce the likelihood of an error in imaging polarimetry.