A switchable and tunable THz metasurface absorber with broadband and dual-band absorption features

Graphene-based tunable broadband terahertz (THz) absorbers have garnered substantial research interest; however, further investigation is still required to expand their functional capabilities and versatility across various applications. In this paper, a dual-control tunable metasurface absorber (DCTMA) is proposed employing a simple structure of graphene and vanadium dioxide (VO₂). The tunability of the DCTMA is achieved through dynamically tuning the chemical potential of graphene, while the phase transition of VO₂ facilitates a transition from broadband to dual-band absorption. The simulation results based on finite-difference time-domain (FDTD) confirm that the proposed structure exhibits broadband absorption of 3.91 THz over 90% in the range of 1-10 THz, maintaining an absorption rate of over 99% within the 4.56-6.47 THz band. While switching to dual-band absorption, two absorption peaks are observed at 2.23-3.49 THz and 7.17-8.19 THz with maximum absorptance values of 97.77% and 93.3%, respectively. Furthermore, the proposed absorber exhibits stable absorption performance at different polarization angles. The proposed DCTMA is a promising candidate for multifunctional applications, including sensing, detection, 6G wireless communication systems, and biomedical technologies.