Perfect terahertz absorber with dynamically tunable peak and bandwidth using graphene-based metamaterials

Abstract

A graphene-based dynamic tunable terahertz (THz) perfect absorber is proposed in this paper. The absorber consists of periodic gold nanoribbons on a graphene-coated silica layer supported by a flat gold substrate, and the graphene is sandwiched between two hexagonal boron nitride (h-BN) layers. We demonstrate that the proposed structure can lead to perfect THz absorption because of strong photon localization surrounding the graphene layer of the structure. The THz absorption may be tuned continuously from 0 to 100% by controlling the chemical potential through a gate voltage. Moreover, the peak position and bandwidth of absorption spectra can be tuned by adjusting the width of the gold nanoribbons and duty ratio. The absorber can maintain high-efficiency light absorption of more than 90% at a wide range of light incidence angles of 0 to 85 deg. Using the existing technology, our design scheme is easy to realize, which will be helpful to promote the development and application of optoelectronic devices.