Ultraviolet and visible double Fano resonances of three-dimensional metamaterials by plasmonic coupling with aluminium surface

Abstract

Abstract We theoretically investigate double Fano resonances (FRs) from the ultraviolet to visible range by combining the array of aluminium 3D split-ring resonators (Al 3D-SRRs) and an Al mirror. The interaction between the first-order (1st) magnetic plasmon (MP) mode of the 3D-SRRs and the 1st surface plasmon polariton (SPP) mode propagating on an Al substrate, and the interaction between the second-order (2nd) MP mode and the 2nd SPP mode generate the double narrow FRs. The 2nd ultraviolet FR of the proposed metamaterial has a high refractive index sensitivity of 240 nm RIU−1 and a figure of merit of 22, suggesting promising applications in ultraviolet sensing.