Achieving Efficient Self‐Driven Full‐Stokes Photodetection in Optically Active Ferroelectric

Full‐Stokes polarization detection, enabling the acquisition of complete polarization information, is crucial across various fields such as target identification, robotic perception, and 3D reconstruction. Nevertheless, achieving efficient multiple polarization state detection simultaneously with high recognition accuracy in a compact device remains a significant challenge. Herein, for the first time, we report an optically active ferroelectric OA 2 EA 2 Pb 3 Br 10 ( 1 , where OA is n‐octylammonium, EA is ethylammonium), capable of realizing a self‐driven full‐Stokes polarization detection. Utilizing the bulk photovoltaic effect in 1 , simultaneous detection of both linearly and circularly polarized light can be achieved without requiring an external bias. The in‐plane photodetection configuration exhibits a high linear polarization ratio of 2.7 and a circular polarization anisotropy factor of 0.46. More importantly, the full‐Stokes polarization detection achieves low average measurement errors for the Stokes parameters of 3.2%–5.3%. This study establishes a new paradigm for the rational design of ferroelectric materials that enable self‐driven, filterless full‐Stokes polarization detection.