Ultrafast TiS ₃ /WS ₂ Polarization‐Sensitive Photodetectors for Intelligent Image Decryption and High‐Capacity Optical Data Transmission

ABSTRACT

Secure optical communication for unmanned aerial vehicles requires integrating hardware‐level visual authentication with high‐speed data transmission. This demands that underlying photodetectors to simultaneously deliver high polarization sensitivity for encrypted imaging and microsecond‐level response for fast decoding. Here, a self‐powered photodetector based on a quasi‐1D TiS ₃ /2D WS ₂ van der Waals heterostructure is demonstrated. Engineering an interfacial unilateral depletion region minimizes carrier transit, enabling an ultrafast zero‐bias response time of 3.53 µs, responsivity of 278 mA/W, and detectivity of 1.14×10 ¹² Jones. Driven by the profound in‐plane structural anisotropy of TiS ₃ , the device exhibits an exceptional polarization ratio of 23 at 405 nm. By combining this high polarization sensitivity with ultrafast switching, the heterostructure naturally operates as a closed‐loop secure communication node. In this integrated system, the polarization ratio initially serves as a physical‐layer key for a convolutional neural network to decrypt visual targets and authenticate spatial identity. Upon successful authentication, the device directly applies its microsecond‐level response to execute multi‐parameter optoelectronic logic operations, decoding high‐density quaternary time‐series data for ASCII payload reception. This establishes a robust optoelectronic platform for integrated secure perception and high‐capacity covert optical networks.