Enhanced Second-Harmonic Generation in Monolayer MoS2 Driven by a BIC-based Nonlinear Metasurface

Dielectric metasurfaces have opened novel routes for nonlinear optics in recent years. In this work, we integrate a nonlinear metasurface with monolayer molybdenum disulfide (MoS
2
) to enhance second-harmonic generation (SHG) from atomically thin MoS
2
. By utilizing bound states in the continuum, we achieve about 600× of SHG enhancement from monolayer MoS
2
on a resonant metasurface relative to suspended monolayer MoS
2
. Moreover, an eigenmode expansion approach is exploited to express second-harmonic power and the corresponding analytical results agree well with the rigorous calculations.