Resonant Excitation Analysis of the Absorption Enhancement of L-Shaped Metasurfaces in Midinfrared Band

Surface plasmon waveguides have attracted a lot of attention in recent years due to their ability conduct light the subwavelength scale. A large number metallic structures been used as and applied integrated photonic circuits. Among these structures, metal-insulator-metal surface waveguide is considered unique advantages. Compared other forms, it more compact thus easier integrate into optical For reasons, we investigated transmission properties waves built MIM absorber consisting gold dielectric. We developed an interference model for concluded that interactions between metal patch substrate are not negligible near field. In addition, magnetic resonance plays equally important role approaching uniform absorption. Absorption spectra with different structural parameters, incidence angles, polarizations were investigated. sharp absorption peak was also found be caused by Rayleigh anomaly. The study reported this paper contributes further understanding physical absorber, expect refine theoretical future eliminate bias near-field coupling.