Tunable Perfect Absorber of Graphene Metamaterial in the Terahertz Band and Its Sensing Properties

Abstract

Herein, a dual-band tunable ideal absorber based on graphene array, and the dynamic tuning performance of the perfect absorber in the terahertz band and its sensing properties based on graphene metamaterials are studied. The absorber shows two perfect absorption peaks at 1.01 and 1.86?THz, with an absorbance of 99.5% and 99.9%, respectively. With an elevation angle in the range of 0°?30° and a frequency in the range of 0.971?1.100?THz or 1.794?1.897?THz, the absorber designed herein can achieve an absorbance greater than 90%. Owing to the superior properties of graphene, dynamic tuning of the absorption frequency band, absorption bandwidth, and relative bandwidth of the absorber can be achieved by adjusting the Fermi level of graphene. In addition, adjusting the relaxation time realizes dynamic tuning of the absorption bandwidth and the absorbance with constant resonant frequency and fixed geometric parameters. Moreover, the sensitivity of the absorber reaches 492.5?GHz/RIU, which can achieve the sensing resolution required for the resonance frequency. This research provides a new concept for the development of high-performance terahertz devices.