Stokes Polarimeter via Characteristic Pattern Strategy by Vortex-PSA Module

This work focuses on a compact and one-shot Stokes polarimeter by vortex characteristic patterns. Unlike previous spatial modulation Stokes polarimeter relying on a mapping strategy with calibration/pretraining images to establish a pixel-to-Stokes relation between the output pattern and the tested Stokes vector, we provide an alternative “Characteristic-Pattern-to-Stokes” strategy for polarization measurement. It involves two key techniques: 1) our proposed vortex polarization state analyzer (vortex-PSA) module, which generates characteristic patterns that are directly interpretable and easy to extract and 2) simple and effective extraction of the output vortex characteristic pattern in the frequency domain. More specifically, based on our proposed vortex-PSA module, the tested Stokes vector turns to a vortex characteristic pattern, whose shape is related to the tested polarization state and can be directly interpreted. Moreover, the vortex characteristic pattern can be decomposed into different harmonic components, making it easy to extract using our pattern decomposition algorithm by Fourier analysis. With our proposed “Characteristic-Pattern-to-Stokes” strategy, we achieved Stokes vector measurement with error metric from 0.0136 to 0.0451, without requiring complex precalibration or pretraining procedures, making the system easy to operate.