Design of a Tunable Absorber Based on Graphene in the THz Range

This paper presents a tunable graphene-based absorber with near-unity absorption in terahertz range. The absorber is composed of the patterned graphene and a metallic reflecting plate spaced by a dielectric layer. The results show that the absorber's normalized bandwidth of 90% terahertz absorbance is over 86% under normal incidence for both TE and TM polarizations when the graphene chemical potential is set as 0.5 eV. The absorber also has the advantage of fexible tunability via electrostatic doping of the patterned graphene. By controlling the chemical potential from 0 eV to 0.6 eV, peak absorbance can be continuously tuned from 0% to 100%. The design scheme is scalable to develop various graphene-based tunable absorber at other terahertz, infrared, and visible frequencies, which may have promising applications in sensing, detecting, and optoelectronic devices.