Multiband tunable perfect metamaterial absorber realized by different graphene patterns

In this paper, the absorption performance of a proposed metamaterial (MM) absorber based on a three-layer graphene structure working in the terahertz (THz) frequency band is studied. By using different types of combined graphene patterns, dual-band, tri-band, and quad-band absorption can be achieved. In the case of tri-band absorption, three absorption peaks with absorption rates of 99.7%, 99.9%, and 99.9% can be found at frequencies of 4.64 THz, 6.45 THz, and 9.71 THz, respectively. In addition, the proposed structure is polarization independent and has the absorption characteristic of wide incident angles. The frequency and the intensity of the absorption peaks can be adjusted by changing the chemical potential and the relaxation time of the graphene and the structural parameters. Therefore, we believe that the proposed graphene MM absorber structure provides flexible design ideas for a multibandwidth MM perfect absorber, and the proposed absorber also can be applied to subwavelength integrated sensors and optoelectronic devices in the terahertz range. (C) 2021 Optical Society of America