Model-based calibration method for Mueller channeled spectropolarimetry

Conventional calibration methods for Mueller channeled spectropolarimeters (MCSP) often estimate the system parameters from the reconstruction results of reference samples. However, limited reconstruction accuracy constrains calibration precision, leading to unsatisfactory performance. In this paper, a model-based calibration method for MCSP is proposed. The MCSP is modeled as a modulation matrix that maps the under-test Mueller spectra to the channeled spectrum. This modulation matrix is derived based on physical laws and then corrected using a reference measurement to account for misalignment, thickness errors, and the spectrometer's point spread function. The Mueller spectra are then reconstructed via convex analysis with sparse regularization. Experimental results demonstrate high accuracy, with a root mean square error (RMSE) of approximately 0.01 and a 40% improvement in accuracy compared to the state-of-the-art dual rotating retarder spectropolarimeter-based calibration method. Notably, the proposed calibration method eliminates the need for prior reconstruction and requires no additional instrumentation, preserving the simplicity of MCSP while promoting its practical applicability.