A wide-angle broadband absorber in graphene-based hyperbolic metamaterials

¹ College of Information Engineering, Huangshan University, Huangshan 245041, P.R. China
² Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing Univ. Aeronaut. Astronaut.), Ministry of Education, College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P.R. China

^a e-mail: nrxxiner@hsu.edu.cn

Received: 23 May 2014
Accepted: 15 July 2014
Published online: 15 October 2014

Abstract

A wide-angle broadband absorber which is realized by periodic structures containing graphene-based hyperbolic metamaterials (GHMM) and isotropic medium is theoretically investigated. The GHMM is composed of monolayer graphene and conventional dielectric, which the refractive index can be tuned by the chemical potential, the thickness of dielectric and phenomenological scattering rates, respectively. A periodic structure of GHMM can obtain a broadband absorption which is shown to absorb roughly 70% (relative bandwidth is larger than 45%) of all available electromagnetic wave in absorption bandwidth at normal incident angle. Compared with some previous designs, our proposed structure has a relative bandwidth over a broad frequency range in mid-infrared. This kind periodic structures offer additional opportunities to design novel optoelectronic devices.