Infrared Optoelectronic Logic Gates and Encrypted Optical Communication Enabled by a b‐AsP/MoTe 2 Heterostructure With Bipolar Photoresponse

ABSTRACT Optoelectronic logic gates (OELGs) that directly convert optical inputs into Boolean electrical outputs offer a promising route toward low‐latency, in‐sensor computing. However, most existing OELGs operate in the ultraviolet‐visible‐near‐infrared (UV‐VIS‐NIR) range and require complex circuits to implement versatile logic operations. Here, we demonstrate a broadband optoelectronic logic device based on a 2D b‐AsP/MoTe 2 heterostructure, which exhibits intrinsically bipolar photoresponses across both near‐ and mid‐infrared (NIR‐MIR) bands under zero bias. The device outputs a positive photocurrent under NIR illumination via photovoltaic effect, and a negative photocurrent under MIR excitation dominated by the photothermoelectric effect. By assigning logic states according to current polarity and magnitude, multiple logic functions including AND, OR, NOR, NAND, NOT, and XOR, are implemented within a single pixel through wavelength‐intensity reconfiguration. Furthermore, the XOR behavior enables a proof‐of‐concept demonstration of encrypted optical communication, including secure transmission of binary text and images using dual‐band optical inputs. These results establish a scalable, compact platform for multifunctional logic‐in‐sensor architectures, with potential applications in intelligent infrared imaging, secure optical networks, and on‐chip processing in multiband photonic systems.