Tunable terahertz perfect absorbers with Dirac semimetal

We propose that perfect light absorption can occur in a planar array of cross sheet with bulk Dirac semimetal (BDS). Comprehensive analysis about single cross sheet with BDS shows that the extinction cross section per unit area can reach 24.8, which is four times as much as that of graphene. Further, the proposed perfect absorber can realize tuning of resonance frequency by changing the Fermi energy and all simulation results can be explained analytically. Moreover, dual-channel perfect absorption is obtained by merely changing the geometric parameters. The high-frequency absorption peak resulting from inter-units electric resonance shows better sensing property. Our results may provide potential applications in optical filter and biological chemistry sensing.