Active graphene metamaterial absorber for terahertz absorption bandwidth, intensity and frequency control

A novel graphene-based metamaterial absorber with actively tunable bandwidth, intensity and frequency, working at the terahertz (THz) spectral region, was designed and numerically investigated in this paper. The actively controlled absorption characteristics in the graphene absorber were achieved by integrating two identical-sized graphene disc elements to construct a supercell, in which two elements of all unit cells were connected respectively by the electrical isolation graphene wires to form selectively electrostatic doping. The surface current distributions and the circuit model analysis were conducted to reveal the absorption mechanism and predict the tuning mechanism. Moreover, by selectively tuning two gate voltages to change the Fermi energy reconfiguration state of two graphene elements, the absorption bandwidth, intensity and frequency of the metamaterial absorber could be actively controlled. In addition, a striking switching contrast was obtained by switching the reconfiguration state of the two discs. Therefore, this work paves a pathway for the realization of actively controlled terahertz waves based on electrically reconfigured graphene metamaterials. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.