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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.

Terahertz (THz) dynamic phase modulator is indispensable in THz wireless communications, high-resolution imaging and radar systems. However, up to now, it is difficult to achieve dynamic tunable phase shift of more than 150 degrees in single-layer transmission mode. In this work, we proposed a THz dynamic large phase modulator based on graphene-metal hybrid metasurface. The simulation results show that, when the Fermi level of graphene changes from 0 eV to 0.86 eV, the phase shift exceeds 176 degrees. By modifying the structural parameters, a phase shift of 170 degrees can be achieved in a bandwidth of 50 GHz. We investigated the physical mechanism of the dynamic phase modulator, and established the relationship between phase shift and Fermi level theoretically. This study paves a new way for realizing dynamic large phase modulation, which is very important for the THz broadband wireless communication, high-resolution imaging and radar system.

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