6533b871fe1ef96bd12d2476
RESEARCH PRODUCT
Near-unity third-harmonic circular dichroism driven by a quasibound state in the continuum in asymmetric silicon metasurfaces
Davide RoccoAndrea TognazziLuca CarlettiCostantino De AngelisMarco Gandolfisubject
PhysicsCircular dichroismSiliconEnergy conversion efficiencynonlinear optics chirality quasi-bound statesPhysics::Opticschemistry.chemical_elementSettore ING-INF/02 - Campi Elettromagnetici02 engineering and technologyState (functional analysis)021001 nanoscience & nanotechnology7. Clean energy01 natural sciencesNonlinear systemQuality (physics)chemistry0103 physical sciencesContinuum (set theory)Atomic physics010306 general physics0210 nano-technologyExcitationdescription
We use numerical simulations to demonstrate third-harmonic generation with near-unity nonlinear circular dichroism (CD) and high conversion efficiency $({10}^{\ensuremath{-}2}\phantom{\rule{4pt}{0ex}}{\text{W}}^{\ensuremath{-}2})$ in asymmetric Si-on-$\mathrm{Si}{\mathrm{O}}_{2}$ metasurfaces. The working principle relies on the spin-selective excitation of a quasibound state in the continuum, characterized by a very high $(g{10}^{5})$ quality factor. By tuning multimode interference with the variation of the metasurface geometrical parameters, we show the possibility to control both linear CD and nonlinear CD. Our results pave the way for the development of all-dielectric metasurfaces for nonlinear chiro-optical devices with high conversion efficiency.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2021-08-25 | Physical Review A |