Nonlinear plasmonic metasurfaces

Nonlinear plasmonic metasurfaces have recently attracted considerable interest, due to their potential for enabling nanoscale nonlinear optics. Here, we review the current progress in this topic while paying special attention to existing challenges. In order to limit our scope, we concentrate on nonlinear metasurfaces utilizing inter-particle and lattice effects and focus on metasurfaces operating close to visible and near-infrared frequencies. We will also critically discuss the short and longer term prospects of nonlinear metasurfaces to start rivalling traditional nonlinear materials in applications.