Resonant chiral effects in nonlinear dielectric metasurfaces

Abstract

We study the resonant enhancement of linear and nonlinear chiroptical effects in asymmetric silicon metasurfaces supporting multipolar Mie resonances and quasi-bound states in the continuum (quasi-BICs). We demonstrate theoretically and observe in experiment the pronounced linear circular dichroism at the quasi-BIC resonances. We further find that both local field enhancement and third-harmonic signal are large for Mie resonances and some quasi-BIC modes. We explain the selectivity of the nonlinear enhancement by employing the concept of critical coupling being more favorable for the modes with moderately large radiative quality factors ($Q$ factors). We demonstrate experimentally strong nonlinear chiroptical response associated with high efficiency of the third-harmonic generation and large nonlinear circular dichroism varying from $+0.918\pm 0.049$ to $-0.771\pm 0.004$ for the samples with different asymmetries. We believe our results suggest a general strategy for engineering nonlinear chiroptical response in dielectric resonant metasurfaces.

23 pages, 5 figures

References in corpus (5)

• Planar chiral metasurfaces with maximal tunable chiroptical response driven by bound states in the continuum
• Metasurfaces with maximum chirality empowered by bound states in the continuum
• Continuous wave second harmonic generation enabled by quasi-bound-states in the continuum on gallium phosphide metasurfaces
• Spin-Preserving Chiral Photonic Crystal Mirror
• Second-harmonic optical circular dichroism of plasmonic chiral helicoid-III nanoparticles

Cited by in corpus (9)

• Applications of Bound States in the Continuum in Photonics
• Nonlinear chiral metaphotonics
• Chiral Dichroism in Resonant Metasurfaces with Monoclinic Lattices
• Nonlinear chiral metasurfaces based on structured van der Waals materials
• Substrate-induced maximum optical chirality of planar dielectric structures
• Scattering matrix for chiral harmonic generation and frequency mixing in nonlinear metasurfaces
• When does nonlinear circular dichroism appear in achiral dielectric nanoparticles?
• Achiral nanostructures: perturbative harmonic generation and dichroism under vortex and vector beams illumination
• Resonant helical dichroism in twisted dielectric metastructures