Nonlinear plasmonic metasurfaces, as a subset of metamaterials, allow for active functionality not found in natural optical materials; including switching, wavelength conversion, routing, adaptive focusing. Metasurfaces in particular are compact, cascadable and easy to fabricate with established planar technologies, and therefore deserve particular attention.
Here we focus on nonlinear plasmonic metasurfaces, where the nonlinear response of the metal is considered in nanostructured plasmonic metasurfaces. Past works have demonstrated that the Lorentz contribution to nonlinear plasmonic metasurfaces is typically negligible. In this work, we discuss the physical reasons why this is true and show experimental results of designs where the Lorentz contribution is maximized, with some surprising results.
Finally, the prospects of these demonstrations for future metasurface applications, including high efficiency wavelength conversion, are discussed.