Graphene-based Salisbury screen metasurfaces at infrared wavelengths

Graphene is an atomically thin carbon sheet with a two-dimensional hexagonal lattice structure that has drawn significant attention in many fields due to its unique electronic and optical properties. In this study, graphene Salisbury screen metasurfaces (GSMs) were theoretically investigated as wavelength-selective plasmonic metamaterial absorbers. The GSMs consist of a top graphene sheet, a middle insulator layer and a bottom reflector. The absorption wavelengths of GSMs with a continuous graphene sheet are demonstrated to be controllable according to the insulator layer thickness, which is similar to the case for a conventional Salisbury screen. The insulator thickness can be used to control the optical impedance to incident light using the graphene as a resistive sheet. GSMs with a periodic micropatch array of graphene can be used to control the absorption wavelength, mainly based on the graphene micropatch size and symmetry in conjunction with the insulator thickness. This wavelength selectivity is mainly attributed to the plasmonic resonance in graphene. In both structures, the chemical potential of graphene can be used to tune the absorbance and the absorption wavelength. These results will contribute to the development of electrically tunable and high-performance graphene-based wavelength-or polarization-selective absorbers or emitters.