Active tunable terahertz resonators based on hybrid vanadium oxide metasurface

Hybrid terahertz (THz) metamaterial resonators have exhibited superior reconfigurable resonant response enabled by active materials, such as liquid crystals, graphene, and semiconductors. However, the tunable range of constitutive parameters of materials is still limited, which leads to the low modulation depth of THz devices. Unlike other phase change materials, vanadium dioxide (VO2) exhibits an insulator-to-metal transition characteristic and the conductivity can be increased by 4-5 orders of magnitude under external stimulus including electric fields, optical, and thermal pumps. Here, we propose an active tunable THz resonator based on a hybrid VO2 metasurface for thermal control. The simulated results show that by external thermal stimulation, we realize the tuning between the single and double resonant modes. The resonant peak at high frequency disappears while the low frequency peak is enhanced with the increasing temperature. The simulated surface electric fields confirm the physical mechanism of the excellent tunable performance that the L-shaped and cross resonances play a dominant role at the low and high temperature, respectively, due to the VO2 phase transition. Such a hybrid VO2 metasurface resonator with tunable characteristics will greatly promote the practical application of THz functional devices, such as modulators, sensors and fillers.