Switchable multichannel terahertz wavefront manipulation based on a VO 2 phase-transition metasurface

Multifunctional control of terahertz (THz) wavefronts remains challenging because resonant meta-atoms typically exhibit fixed electromagnetic responses. Vanadium dioxide (VO 2 ) with an insulator-to-metal phase transition offers an effective route for actively switching the dominant resonant pathway in THz metasurfaces. Here, we propose a switchable reflective metasurface based on a six-layer anisotropic VO 2 meta-atom. By combining propagation and Pancharatnam–Berry (PB) phases, the metasurface enables independent wavefront control for left- and right-handed circular polarizations. The VO 2 phase transition switches the dominant resonant layer from the lower Au cross resonator at 1.17 THz in the insulating state to the upper patterned VO 2 resonator at 1.24 THz in the metallic state. Numerical results demonstrate four polarization-multiplexed holographic channels, dual-beam splitting, deflected vortex-beam generation, and multichannel orbital-angular-momentum routing.