Terahertz phase modulator based on a metal-VO₂ reconfigurable metasurface

Actively controlling the phase of a terahertz (THz) wave is of great significance for beaming, tunable focusing, and holography. We present a THz phase modulator based on an electrically triggered vanadium dioxide (V O ₂) reconfigurable metasurface. The unit cell of the device consists of two split-ring resonators embedded with a V O ₂ ribbon. By electrically triggering the insulator-to-metal transition of V O ₂, the resonance mode and resonance intensity of the unit cell can be dynamically controlled. The simulation results show that the structure can achieve a phase shift of about 360° in the range of 1.03-1.13 THz, and the reflection amplitude can reach 80%. The device has potential applications in THz imaging, radar, broadband wireless communications, and array phase control.