Graphene based polarization independent Fano resonance at terahertz for tunable sensing at nanoscale

A two-dimensional metamaterial structure consisting of polyimide layer covered by a square disk of monolayer graphene and the gold symmetrical split resonance ring is proposed and investigated. Our simulations indicate that the Fano resonance mode in the terahertz range can be generated by this metamaterial structure, and also utilized for nanoscale sensing. The maximum frequency shift is 1671.61 GHz, and the frequency sensitivity is 1.18 THz/RIU for 2-nm-thick analyte. Furthermore, by adjusting the Fermi level of graphene, the resonance frequency can be tuned actively. Different from the Fano resonance excited by asymmetric structure, the proposed structure is polarization-insensitive and can perform well with both TE and TM waves ? 2019 Elsevier B.V.