Polarimetric calibration method for the fore-optics of a channeled spectropolarimeter

A channeled spectropolarimeter is a powerful tool for the simultaneous measurement of the intensity, spectral, and polarization information of a target. However, the fore-optics introduce additional polarization information, which leads to inaccurate reconstruction of the Stokes parameters. In this study, we propose a simple method for polarimetric calibration and Stokes parameters reconstruction for a fieldable channeled spectropolarimeter. The polarization effects of the fore-optics and phase factors of the high-order retarders at varying view angles are considered and calibrated independently using a single reference beam. Moreover, the misalignment of the retarders is also considered. Simulation results demonstrate that the polarization effects of fore-optics can be precisely determined, enhancing the measurement accuracy of the Stokes parameters by approximately an order of magnitude. The effectiveness of the proposed method is also verified experimentally.