Numerical Analysis on Ribbon-Array-Sheet Coupled Graphene Terahertz Absorber

A terahertz tunable graphene ribbon-array coupled with a sheet absorber, which has the near-unity absorption and wide absorption bandwidth, is proposed and studied in this letter. The proposed structure can strongly trap the incident wave and enhance its absorption. By optimizing the parameters of the structure, a perfect absorption over 99.99% can be achieved numerically in the far infrared region. The absorption peaks can be modulated by adjusting the chemical potentials of graphene. We also investigate the absorption variation of the proposed absorber by varying the structure parameters. Furthermore, the geometry of the proposed graphene absorber is very simple, so the method of chemical vapor deposition can be used to manufacture the proposed absorber.