ReS2/MoSe2 Van der Waals Heterostructure Photodetectors for Polarization Imaging and Polarization-Encoded Optical Communication.

Two dimensional (2D) materials with anisotropic optoelectronic properties provide a feasible solution for polarization photodetectors, however, it is challenging to achieve simultaneous high responsivity, fast photoresponse, and good anisotropic ratio of the photocurrent (I_ph-max/I_ph-min). In this work, a polarization-sensitive photodetector based on ReS₂/MoSe₂ van der Waals heterostructures is constructed for type-II energy band alignment with a clean contact interface. Under 532 nm laser irradiation, the photodetector has both high responsivity (89.4 A W^-1), high-speed response (≈30.5 µs/≈36.2 µs), and high anisotropy ratio of 3.23. The performance of the device has been enhanced for multifunctional applications, including single-pixel polarization imaging and encrypted optical communication by combining Morse code with polarization encoding, demonstrating its potential in polarization-related optical information applications.