Enhanced THz absorption of graphene cavity-based electromagnetic metamaterial structures

We investigate THz absorption characteristics of graphene cavity-based electromagnetic metamaterial structures by using the conductivity characteristic matrix method. We demonstrate that the proposed structure can obtain ideal terahertz absorption due to the strong localization of photons in the defect layer of the electromagnetic metamaterial structure. The THz absorption can be continuously adjusted from 0% to 100% by controlling the chemical potential of graphene through a gate voltage. The maximum THz absorption value can be tailored by adjusting the incident angle or the period number of the two PCs with respect to the graphene layer. The position of the THz absorption peak can be adjusted by changing the thickness ratio of the layers constituting the electromagnetic metamaterial structure. Our proposal may have potentially important applications in photodetectors, saturable absorbers, and photovoltaics.