Sensing and switching capabilities of a graphene-based perfect dual-band metamaterial absorber with analytical methods

In this paper, the simultaneous sensing and switching performance of a graphene-based plasmonic dual-band absorber in the terahertz region has been demonstrated and investigated. Due to the high confinement of graphene surface plasmons and the hydrophobic nature of graphene, the structure can be used as a refractive index sensor in biomedical applications such as detection of impurities of water, cancer cells, and STMV virus. The simulation results show an ultrahigh sensitivity of 360 THz/RIU and figure of merit of 654.54 R I U − 1 . Moreover, variation of the graphene chemical potential leads to a switching function between the perfect absorption and total reflection states, with the high extinction ratio of 12.15 dB and ultrafast response time of 1.5 ps. Two analytical methods of equivalent circuit model and transmission matrix have been used to validate the suggested idea of the proposed graphene-based structure. We have shown that there is a good agreement between the theoretical and simulation results. The specifications of our suggested structure are tunability, ultrahigh sensitivity, high extinction ratio, ultrafast response time, and simple design, which pave the ways for design and implementation of other multi-application terahertz plasmonic structures based on graphene in the future.