Tunable plasmonic absorber in THz-band range based on graphene arrow-shaped metamaterial

Abstract

The tunable selective absorber consisting of periodic arrow-shaped graphene arrays that operates in the far infrared and terahertz range is proposed. It is achieved by depositing a set of arrow-shaped graphene ribbons on a SiO2 dielectric spacer. The absorption characteristics of the structure are investigated by the Finite Difference Time Domain (FDTD) method. The results show that when the Fermi level and relaxation time increase at the same time, the maximum pure absorption increases from 0.0109 to 0.1276, which is improved by nearly 12 times. Moreover, when the relaxation time is increased from 0.1 ps to 1.0 ps, the maximum value of the absorption peak increases from 0.0162 to 0.1155. In addition, this paper also conducts a comparative study on the bisymmetric arrow-shaped graphene structure based on this structure. The absorption spectrum of this structure shows a multi-peak phenomenon, which can achieve the purpose of selective absorption and individual modulation. The research results have certain guiding significance for the design of next–generation graphene-based perfect terahertz absorbers, and can be applied to the fields of label-free biomedical sensing, photodetectors and photonic devices.