Silver mirror for enhancing the magnetic plasmon resonance and sensing performance in plasmonic metasurface

Abstract

Abstract We report a novel method for enhancing magnetic plasmon resonances (MPRs) and sensing performance of metasurface consisting of a 1D Ag nanogroove array by using an opaque Ag mirror. The Ag mirror can block the transmission channel of light, so the radiative damping of MPRs excited in Ag nanogrooves is strongly reduced, and therefore the linewidth of MPRs is noticeably decreased. Because of ultra-narrow bandwidth and great magnetic field enhancement at MPRs, the metasurface shows very high sensitivity (S = 700 nm RIU−1, S* = 70 RIU−1) and figure of merit (FOM = 100, FOM* = 628), which holds great potential in the label-free biomedical sensing.