Stable b‐AsP/InSe Mid‐Infrared Detector with High Polarization‐Sensitivity for Target Feature Discrimination

The development of next‐generation polarized mid‐infrared imaging systems demands miniaturization, high polarization ratio, room‐temperature operation and atmospheric stability. Compared to bulk materials, 2D anisotropic materials provide a new route for realizing miniaturized polarized photodetectors. However, their infrared sensing capabilities, particularly for detecting weak infrared thermal radiation, are limited by low polarization extinction ratio (PER), narrow spectra response and short‐term stability. Here a blackbody‐ and polarization‐sensitive infrared detector based on moderated arsenic doped black phosphorus (b‐As 0.7 P 0.3 ) and indium selenide (InSe) heterostructure is proposed to improving these issues. The device achieves high infrared polarization detection performance with a PER of 244, broad spectra with cut‐off wavelength of 4.42 µm and exhibits moderate stability without obvious degradation. Benefiting from these excellent performances, sensitive non‐dispersive infrared multi‐gas detection and high‐contrast weak target thermal radiation imaging are demonstrated. This work provides a new way for developing next‐generation stable polarized mid‐infrared detectors operating at room temperature.