Multiband tunable perfect absorber based on graphene metamaterials

Abstract Graphene, due to its high optical transparency and tunable conductivity, is commonly used in the design of tunable perfect absorbers. Based on critical coupling theory, we designed a new metasurface structure of multi-band tunable perfect absorber consisting of silicon dimers, a graphene layer, a silica dielectric layer, and a silver layer. This new metasurface structure achieves perfect multi band absorption in near-infrared, there are three nearly perfect absorption bands at 1138 nm, 1178 nm, and 1248 nm, each exhibiting over 90% near-uniform absorption. In addition, by varying the Fermi level of the graphene layer, the absorption efficiency of these three bands can be actively tuned. The proposed perfect absorber has a simple structure and can be fabricated using standard nanofabrication techniques. We hope this work can advance the engineering applications of multi-band tunable perfect absorbers and promote their potential use in novel photodetectors and optical modulators.