Broadband tunable metasurface absorbing device in the terahertz band based on single-layer graphene

A tunable terahertz broadband absorber using rectangular and L-shaped coupling is designed. The designed terahertz absorber is a classically three-layer construction with a gold foil as the bottom. The structure mainly consists of an electrically tunable graphene material in the top layer, a dielectric constant SiO 2 with [Formula: see text], a middle sandwich, as well as gold flakes on the bottom layer. The absorption response is realized within the region of 2.81–6.50[Formula: see text]THz with more than 99.9% absorption, and the excellent absorption is obtained at [Formula: see text] [Formula: see text]THz and [Formula: see text] [Formula: see text]THz. The impedance of the receiver is calculated through impedance theory, which perfectly verifies its good absorption frequency band. The influence of the physical parameters in the intermediate layer on the absorber was studied, and the best comprehensive performance was obtained at [Formula: see text]m. Finally, the case of tuning the Fermi level of graphene to [Formula: see text] [Formula: see text]eV by an applied voltage was also studied, and the best absorption was obtained. In general, the absorber exhibits good absorption in the terahertz band. This finding indicates the potential for better application of the absorber in detection. This design has potential for application in optical switches, modulators and energy harvesting, as well as providing more inspiration for the reaction of terahertz broadband absorbers designs.