LCVR-based Stokes polarimeter: principles and evaluation

The polarimetric imaging system can acquire not only the target's two-dimensional light intensity distribution information but also the Stokes polarization vector information corresponding to the target light intensity distribution. The Stokes vector information can enhance the target's contrast, highlighting the target from the complex background information. The LCVR-based Stokes polarimeter uses a Liquid Crystal Variable Retardation (LCVR) instead of the rotating waveplate in conventional measurement techniques, which enables polarization measurements without moving parts. This paper first introduces the measurement principle of the Stokes vector method, the working principle of LCVR, and the parameters of commonly used evaluation indicators in polarimetric measurement systems. Then, a two-channel single LCVR-type polarimeter measurement scheme is proposed, which uses a split beam element (prism PBS, Savart plate, or Wollaston prism) and a single LCVR to obtain the full Stokes parameters of the target. Then the measurement matrix and light intensity calculation formulas for the polarimeter and polarization spectrometer were derived, and the evaluation parameters of the system (CN, RAD, EWV) were calculated. The study and evaluation analysis provide some theoretical references for studying the LCVR-based Stokes polarimeter.