Dynamically tunable perfect THz absorption in graphene-based metamaterial structures

We investigate THz absorption properties of a graphene-based metamaterial structure composed of a graphene/SiC defect layer placed on one side of the periodic array of Si and SiO2 layers. We demonstrate that the proposed structure can lead to perfect THz absorption because of strong photon localization in the defect layer of the structure. The maximal absorption value and corresponding frequency can be tuned by controlling the Fermi energy through a gate voltage. Moreover, the absorption peak value is insensitive to the incident angle and period number. The position of the THz absorption peak can be tailored by adjusting the thickness spacer layer SiC. By applying an external magnetic field, one can dynamically manipulate the left-handed circularly polarized (LCP) or right-handed circularly polarized (RCP) absorption. Our proposal may have potentially important applications in optoelectronic devices such as circular polarized wave sensors, photodetectors and absorbers.