Giant enhancement of second-harmonic generation from a nanocavity metasurface

Nonlinear plasmonic metasurfaces are compatible with complementary metal oxide semiconductor technology and highly promising for on-chip optical switching and modulations and nanoscale frequency conversions. However, the low nonlinear-optical response of metasurface devices limits their practical applications. To circumvent this constraint, we propose the design of a nanocavity plasmonic metasurface, in which the strong light localization in the nanocavity can be used to boost the efficiency of second-harmonic generation. Compared with the single-layer counterpart, experimental results show that the intensity of the second-harmonic waves in the nanocavity metasurface is enhanced by similar to 790 times. The proposed nanocavity plasmonic metasurfaces in this work may open new routes for developing highly efficient nonlinear metacrystals for on-chip nonlinear sources, nonlinear image encryption, information processing, and so on.

Automated summary

Nonlinear plasmonic metasurfaces have great potential for on-chip optical applications, but their low nonlinear response has been a limitation. A new design of nanocavity plasmonic metasurface was proposed in this study to enhance second-harmonic generation efficiency through strong light localization. This advancement may lead to highly efficient nonlinear metacrystals for various applications such as on-chip nonlinear sources and image encryption.