Dual-gated tunable absorption in graphene-based hyperbolic metamaterial

The use of a dual-gated tunable absorber in graphene-based hyperbolic metamaterial (GHMM) in the near-infrared frequency range was investigated. The horizontal and vertical parts for relative permittivity of GHMM, which consists of monolayer graphene and conventional dielectric, were tuned using the chemical potential. To obtain a large absorption, GHMM was placed on top of a stacked structure containing dielectric and graphene layers and a copper reflector was placed at the bottom. The dual-gated absorber had multiband absorption, which was tuned using the chemical potential of graphene and GHMM. This study focuses on the variation of the absorption with change in the chemical potential and dielectric thickness. The results show that multiband absorption could be attained when chemical potential and dielectric thickness was changed. Broadband absorption could be generated when the frequency ranged from 215 THz to 250 THz. This phenomenon may be valuable for a variety of important applications including optical communication technology and near-infrared stealth communication.