Switchable Dual Broadband Tunable Metamaterial THz Absorber Using VO2 and Graphene Structure

In this paper, we propose a terahertz absorber with dynamically alterable dual-broadband absorption properties within the terahertz frequency spectrum. It utilizes a composite metamaterial composed of graphene as well as vanadium dioxide (VO
2
). By leveraging the transition between phases of VO
2
and the electrical tunability of graphene, the absorber achieves dynamic control over its absorption characteristics. Within the metal state of VO
2
and graphene Fermi energy level set to zero, it exhibits wide-ranging high-frequency absorption exceeding 90% from 8.65 THz to 10.30 THz. In the insulator phase of VO
2
and a Fermi energy level of 0.7 eV in graphene, greater than 90% absorption occurs within the interval of 2.85 THz to 4 THz. Additionally, when VO
2
exhibits a metallic state and graphene has energy at the Fermi level of 0.7 eV, greater than 90% absorption is achieved in both regions, from 2.25 THz to 3.75 THz and from 8.75 THz to 10.25 THz. This dual switchable wideband absorber holds promise for applications such as filtration, concealing objects and detecting, and controls in the terahertz regime.