High discrimination infrared polarimetry via intrinsic anisotropic photogating in black phosphorus meta-polarization detectors

Filterless miniaturized polarization photodetectors are essential for next-generation ultracompact optical and optoelectronic systems. However, achieving high polarization discrimination and high sensitivity over a broad wavelength range based on a simple device structure remains difficult. Here, we address this challenge by leveraging a band modulation effect induced by intrinsic anisotropic photogating. We realize a meta-polarization-detector consisting of a black phosphorus (BP) flake partially supported by SiO₂ with trap states and partially supported by hexagonal boron nitride (hBN) with almost no trap states. The band distribution and hence the self-powered photocurrent are significantly influenced by light illumination in a polarization dependent manner. The polarization extinction ratio (PER) tending to ∞/-∞ is achieved over the near- to mid-infrared range with high specific detectivity. Further, our device achieves PER = ∞/-∞ under blackbody radiation. The specific polarization angle detectivity reaches 3 × 10⁷ cm Hz^0.5 W^-1 degree^-1. Despite utilizing the photogating effect, the photoresponse times are of the order of microseconds. Our work provides a promising approach for high performance ultracompact polarization photodetectors.