Dual-controlled tunable terahertz coherent perfect absorption using Dirac semimetal and vanadium dioxide

Abstract

We proposed and investigated a dual-controlled broadband tunable terahertz metamaterial coherent perfect absorber based on Dirac semimetals and vanadium dioxide (VO2). In such an absorber, the absorptivity at 2.75 THz can be varied between 0.13% and 99.4% by adjusting the phase difference between the incident waves. When VO2 is in the insulating state and Fermi energy (EF) of the Dirac semimetals is 95 meV, the proposed device behaves as a tunable perfect single-band absorber. Further, the resonance frequency of the proposed absorber shifts from 1.46 THz to 1.86 THz by varying EF of the Dirac semimetals from 90 to 110 meV. Therefore, with the transition of VO2 from the insulator to metal state, the designed system functions as a tunable perfect dual-band absorber. Furthermore, by using these two independent controls in series, broadband absorption with an absorption rate greater than 90% can be obtained.