Collective Excitations in Nonlinear Metasurfaces: Challenges and Possibilities

Abstract

Nonlinear metasurfaces have recently emerged as promising candidates to enable nanoscale/flat nonlinear optics. Here, we discuss our latest work to develop more efficient nonlinear metamaterials by using high-Q-factor collective lattice excitations known as surface lattice resonances (SLRs). We also demonstrate how conversion efficiencies of metasurfaces can be further improved by embedding nonlinear metasurfaces into multipass cells. Superlinear dependence of second-harmonic generation (SHG) on the number of passes through the metasurface has been measured, confirming successful phase matching during the proof-of-principle experiment.