Harmonizing terahertz waves: unleashing the versatility of a multi-mode metamaterial absorber

An absorber composed of stacked graphene rings, vanadium dioxide (VO2) patches and metal reflectors separated by dielectric layers is proposed and numerically simulated using the finite element method (FEM). This absorber exhibits a multitude of absorption modes, including ultra-wideband, double-narrow band, and switchable multi-band perfect absorption. The physical mechanism behind perfect absorption is thoroughly investigated through the utilization of impedance matching theory, multiple interference theory (MIT), and coupled mode theory (CMT). Detailed analysis of the electric field further reveals the underlying physical phenomena. Notably, the absorber showcases the ability to dynamically adjust absorption performance by modifying the conductivity of (VO2) and the Fermi level of graphene, while maintaining consistently high absorption levels. The proposed multi-mode absorber maintains good performance within wide incidence angle. Based on the above advantages, this absorber holds promising potential for advancements in energy harvesting and sensor technologies.