Structured vanadium dioxide metamaterial for tunable broadband terahertz absorption

Abstract

A tunable broadband terahertz (THz) absorber based on vanadium dioxide (VO 2 ) is proposed, which is composed of a structured VO 2 metamaterial layer, a dielectric layer, and a metal layer. The simulation results show that the peak absorption intensity of the absorber can be dynamically adjusted from 3.6% to 100% by changing the conductivity of VO 2 . When the conductivity of VO 2 is 2×10 5 S/m, an excellent broadband absorption phenomenon appears, and the bandwidth of absorption rate greater than 90% is as wide as 4.10 THz from 3.25 THz to 7.35 THz. The impedance matching theory and the electric field distribution are used to explain the physical mechanism of the proposed absorber. In addition, the absorber shows the advantages of polarization-insensitiveness and wide-angle absorption. It is expected that this absorber can have potential applications such as modulators and photoelectric switches.