Ultrafast Optical Modulation of Second- and Third-Harmonic Generation from Cut-Disk-Based Metasurfaces

摘要

We design and fabricate a metasurface composed of gold cut-diskudresonators that exhibits a strong coherent nonlinear response. We experimentallyuddemonstrate all-optical modulation of both second- and third-harmonic signals on audsubpicosecond time scale. Pump−probe experiments and numerical models showudthat the observed effects are due to the ultrafast response of the electronicudexcitations in the metal under external illumination. These effects pave the way forudthe development of novel active nonlinear metasurfaces with controllable andudswitchable coherent nonlinear response.