Correction strategy of azimuthal bias in Mueller matrix polarimetry for multilayer birefringent media

Mueller matrix polarimetry is widely harnessed in biomedical studies and clinical applications as a powerful tool, enabling comprehensive and quantitative characterization of the optical and structural properties of tissue and cell specimens. However, for complex tissue specimens containing multilayer birefringent microstructures, we find a bias existing between all Mueller matrix-derived linear birefringence azimuth parameters and ground truth, placing critical decision-making at risk in biomedicine using polarimetry. In this paper, we dive deep into the underlying rationale of azimuthal bias in multilayer birefringent structures, proposing a sandwiched configuration hypothesis to offer a rigorous theoretical explanation for the azimuthal bias. Based on the theoretical analysis, we propose a correction strategy, which introduces a correction factor to debias the Mueller matrix-derived linear retardance azimuth parameters. Substantial experimental results on both monolayer and multilayer phantoms demonstrate the plausibility of the sandwiched configuration assumption and the effectiveness of the proposed correction method in alleviating azimuthal bias. The corrected azimuthal parameters enable quantitative and precise determination of linear birefringent orientation in complex layered media, facilitating the biomedical application of Mueller matrix polarimetry, such as in histopathology.