One Metasurface for Four‐Channel Terahertz Wavefront Manipulation Based on Vanadium Dioxide

ABSTRACT Benefiting from the extraordinary ability of manipulating lightwaves at the subwavelength scale, metasurfaces are expected to achieve multifunctional and multichannel integration to increase information capacities. However, their practical application has been limited by fixed electromagnetic responses post‐fabrication. To overcome this constraint, we propose a dynamically tunable metasurface that leverages the insulator‐to‐metal phase transition of vanadium dioxide (VO 2 ), which synergistically combines the geometric (Pancharatnam‐Berry) phase and the propagation phase to overcome the limitations of static or single‐channel devices. This architecture integrates four independent wavefront‐manipulation channels on a single platform, enabling switching between functionalities for linearly polarized (LP) and circularly polarized (CP) incitations via thermal actuation. When VO 2 in its insulating state, the metasurface operates as a spin‐decoupling device under CP incidence, enabling independent wavefront engineering for left‐handed circularly polarized (LCP) and right‐handed circularly polarized (RCP) waves. Upon transition to the metallic state, it serves as a polarization multiplexer for orthogonal LP waves. By integrating four distinct operational modes on a single dynamically reconfigurable platform and employing simple thermal switching—rather than complex control mechanisms—this work demonstrates a significant advance in functional integration and practical feasibility for applications in terahertz communication, holography, and sensing.