Nonlinear optics at the nanoscale is severely limited by the small departure of available materials from linear behavior. Despite intense efforts placed into overcoming this problem using multiple strategies for enhancing the near-field light intensity, all-optical active nanodevices remain a challenge. Here we introduce a material-independent scheme for quantifying the enhancement of the nonlinear response in nanostructures assisted by proximal metallic or dielectric nanoresonators. The proposed figures of merit, which we apply to configurations of current interest incorporating 2D materials and dielectric cavities, can be generally used to optimize nonlinear nanoscale elements.

Peer Reviewed