Surface plasmon polaritons enhanced magnetic plasmon resonance for high-quality sensing

Abstract We investigate the metamaterials consisting of top layer U-shaped metallic split-ring resonators, the middle thin dielectric layer, and the bottom thick metal film, which can realize high-quality refractive index sensing. When propagating surface plasmon polaritons are introduced, two ultra-narrow-band hybridized modes will appear, whose full width at half maximum can reach up to 2.5 nm. Because of the ultra-narrow linewidth and huge magnetic field enhancement at hybridized modes, the metamaterials display very high sensitivity ( S = 912 nm RIU −1 , S * = 95.64 RIU −1 ) and large figure of merit (FOM = 364.8, FOM*= 160 740.34), which has great potential in label-free biomedical sensing.