Terahertz four-channel holographic encryption metasurface relying on the phase transition of vanadium dioxide

Abstract In the field of terahertz (THz) waveband information security, conventional devices face limitations due to their fixed electromagnetic responses, making it difficult to meet the demands for dynamic encryption and multifunctional integration. This study proposes a reconfigurable reflective metasurface that integrates phase-encoded encryption with a multi-parameter ‘temperature-polarization’ key mechanism. Leveraging the metal–insulator transition (MIT) of vanadium dioxide (VO 2 ), we realize four independent holographic channels in the 0.8 THz band by coordinating orthogonal x/y linear polarizations with the material’s phase transition. An iterative Gerchberg–Saxton (GS) algorithm is employed to encode target information into phase distributions bound to specific hardware-level keys. Compared with traditional single-parameter metasurfaces, the proposed design utilizes the global thermal control of VO 2 and polarization multiplexing to significantly expand the key space and information isolation. This approach provides a new paradigm for THz information security that combines dynamic functionality with enhanced physical-layer encryption.