Terahertz metamaterials for broadband, high modulation depth modulator, and tunable dual-band absorber based on metal-vanadium dioxide hybrid structure

Abstract

Terahertz metamaterials for broadband, high modulation depth modulating, and tunable dual-band absorbing are designed based on the similar composite structure of metal and vanadium dioxide film arrays. By using external excitation to induce the insulator-metal phase transition of the vanadium dioxide layer, the transmission characteristics of the metamaterial can be manipulated. High modulation depths of more than 80% are achieved in the range of 0.2–0.8 THz, and the bandwidth width with modulation depths exceeding 60% is up to 140%. By increasing the dielectric thickness and adding a metal ground, the initial broadband modulator can be switched to a dual-band absorber when the vanadium dioxide is in the metal phase. Furthermore, the modulation effect and the absorption performance exhibit insensitive characteristics to the polarization angle of incident waves. This work provides potential applications in broadband modulation of terahertz communication as well as dual-band absorption for terahertz detection.