Resonance-enhanced generation of optical harmonics from dielectric metasurfaces

Nonlinear dielectric metasurfaces provide a promising platform to control and manipulate the optical frequency conversion at the nanoscale, suggesting new applications in imaging, lasing, and sensing. Here, we engage symmetry-broken silicon metasurfaces to enhance the second- and third-harmonic generation. We design and fabricate amorphous silicon metasurfaces supporting optical bound states in the continuum and guided-mode resonances, which greatly boost light-matter interaction resulting in several-order enhancements in both second-and third-harmonic generation.