Harmonic Generation by Metal Nanostructures Optically Coupled to Two-Dimensional Transition-Metal Dichalcogenide

摘要

Rigorous electrodynamical simulations based on the nonlinear Drude model are performed to investigate the influence of strong coupling on harmonic generation by periodic metal gratings. It is shown that a thin dispersive material with a third-order nonlinearity strongly coupled to surface plasmon-polaritons significantly affects even harmonics generated solely by the metal. The physical nature of this effect is explained using a simple analytical model and further supported by numerical simulations. Furthermore, the behavior of the second and third harmonics is investigated as a function of various physical parameters of the model material system, revealing highly complex dynamics. The nonlinear optical response of two-dimensional few-layer WS2 with both second- and third-order susceptibilities coupled to a periodic plasmonic grating is shown to have a significant effect on the second harmonic generation of the metal.