Theoretical Study of Enhanced Plasmonic–Photonic Hybrid Cavity Modes in Reciprocal Plasmonic Metasurfaces

A new configuration for metasurface construction is presented to exhibit potential multi-functionalities including perfect absorption, bio/chem sensing, and enhancement of light–matter interaction. The reciprocal plasmonic metasurfaces discussed here are composed of two plasmonic surfaces of reciprocal geometries separated by a dielectric spacer. Compared to conventional metasurfaces this simple geometry exhibits an enhanced optical performance due to the hybrid plasmonic–photonic cavity. The discussed reciprocal metasurface design further enables effective structural optimization and allows for a simple and scalable fabrication. The physical principle and potential applications of the reciprocal plasmonic metasurfaces are demonstrated using numerical and analytical approaches.