Tunable terahertz absorption in graphene-based metamaterial

• A tunable graphene-based terahertz absorber is composed of a periodically patterned graphene structure and a metal ground plane spaced by a thin SiO2 dielectric layer.
• The perfect absorption can be achieved by using a single layer of graphene-based metamaterial structure at a fixed Fermi energy level.
• The absorption peak can be dynamically controlled over a broadband frequency range by adjusting the gate voltage without re-optimizing or re-fabricating the physical structure.

One of the most important advantages of graphene is the capability of dynamically tuning its conductivity by means of chemical doping or gate voltage. Based on this property, we proposed a tunable graphene-based terahertz absorber composed of a periodically patterned graphene structure and a metal ground plane spaced by a thin SiO2 dielectric layer. Our calculated results show that a perfect absorption can be achieved by using a single layer of graphene-based metamaterial structure at a fixed Fermi energy level. Moreover, the calculated electric field and power loss distributions enable us to reveal the absorption mechanism of the designed absorber. More importantly, we found that the absorption peak can be dynamically controlled over a broadband frequency range by adjusting the gate voltage without re-optimizing or re-fabricating the physical structure. This work may provide a further step in the development of compact tunable devices, such as tunable sensors and absorbers, switches, and slow light devices.