Multiple plasmonic resonance excitations on graphene metamaterials for ultrasensitive terahertz sensing

Abstract

A three-dimensional graphene metamaterial structure consisting of dielectric pillar arrays covered by graphene monolayer with metal layer underneath is proposed and investigated, which can realize the efficient excitations of multiple plasmonic resonance modes under incident terahertz (THz) wave. The multiple plasmonic resonance modes are highly sensitive to the change of analyte refractive index and thickness, and the frequency sensitivity of each resonance mode can reach up to 1.402, 1.687 and 1.643 THz per refractive index unit, respectively. By controlling the Fermi level of graphene, the resonance frequency can be tuned dynamically. Moreover, the proposed structure has three absorption peaks with absorptivity more than 95%, it is polarization-insensitive and can perform very well in a wide incident angles for transverse electric and transverse magnetic waves. This proposed structure can be utilized for active THz plasmonic devices such as multiple channel sensors and absorbers.