Broadband multiparameter-tunable terahertz metasurfaces for dynamic wavefront manipulation based on VO₂ phase transition

Abstract This study introduces a broadband tunable multifunctional terahertz (THz) metasurface platform based on vanadium dioxide (VO 2 ) phase transition. The proposed meta-atom design achieves bistable electromagnetic responses through a hybrid resonant architecture combining a Cu-VO 2 composite hexagonal ring and a VO 2 rectangular patch. In the insulating state, the meta-atom’s response is dominated by the Cu-VO 2 hexagonal ring, enabling full 2π phase coverage across 2–6 THz through structural rotation. Transitioning to the metallic state shifts the dominant response to the VO 2 rectangular patch, which maintains stable reflection coefficient while providing complete 2π phase coverage over 4.8–7.1 THz via rotational tuning, demonstrating remarkable phase modulation performance. Through systematic arrangement of these meta-atoms, we demonstrate three distinct classes of phase-reconfigurable metasurfaces, including an anomalous reflection and beam splitting metasurface that dynamically controls reflection and azimuthal angles, a reconfigurable orbital angular momentum (OAM) generator with switchable topological charges, and a deflected OAM generator that simultaneously manipulates reflection angle, azimuthal orientation, and topological charge. All metasurface configurations exhibit dynamic phase reconfigurability through VO 2 state modulation, with comprehensive numerical simulations validating their broadband wavefront manipulation capabilities. This work offers significant potential for advanced applications in THz communications, high-resolution sensing, and information encryption. The proposed architecture overcomes conventional limitations in tunable THz devices by enabling independent control of multiple wavefront parameters through a single reconfigurable platform.