Reconfigurable multifunctional terahertz metasurface for multidimensional information security

Reconfigurable metasurfaces with multiple degrees of freedom provide an important platform for high-capacity terahertz wavefront manipulation and physical-layer information security. Here, we propose a thermally reconfigurable terahertz metasurface based on the synergistic control of the VO 2 phase transition and spin decoupling, enabling four addressable wavefront responses within a single device through joint control of the VO 2 phase state and incident circular polarization. In the low-temperature state, LCP and RCP incidence generate an l = +1 vortex beam and the holographic image “G,” respectively; in the high-temperature state, the two spin channels reconstruct the holographic image “C” and generate an l = +2 vortex beam, respectively, thereby enabling selective switching between vortex-beam generation and holographic imaging across different temperature–spin channels. Building on this functionality, the operating frequency is further introduced as an additional addressing dimension to establish a multidimensional physical key space jointly defined by the spin state, VO 2 phase state, and frequency, enabling channel-resolved information encryption and selective decryption. The encoded information can be correctly reconstructed and decoded only when the input physical parameters match the predefined key combination; a key mismatch prevents recovery of the target plaintext. By integrating phase-transition reconfigurability, spin-selective wavefront manipulation, and multidimensional physical-key encoding on a single metasurface platform, this scheme provides a new approach to terahertz multichannel information multiplexing and physical-layer secure communications.