Multi-Band High Refractive Index Susceptibility of Plasmonic Structures with Network-Type Metasurface

We theoretically propose a simple plasmonic structure with network-type metasurface consisting of double-layer metal-dielectric network-type metasurface on the two-layer dielectric films. Multiple reflection bands with minimum full width at half maximum of 3 nm are achieved in the visible and near-infrared regions due to the excitation and hybridized coupling of localized surface plasmons, photonic mode, and optical cavity mode. The plasmonic structure with network-type metasurface also shows highly tunable refractive index sensing performance. The maximum sensitivity to the refractive index (RI) change reaches to 596 nm/RIU (RIU: refractive index unit). The figure of merit can reach as high as 68.57. These results show that the plasmonic structure with network-type metasurface could pave a new way for the high-performance multi-band devices such as sensors and filters.