External chirality enhancing downconversion in a waveguide-coupled nonlinear plasmonic metasurface

Tsafrir Abir*, Symeon Sideris, Tal Ellenbogen

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review


Metasurfaces, typically constructed from spatial arrangements of localized building blocks, can enhance light-matter interactions through local field enhancement or by coherent coupling to extended photonic modes. Recent works have explored how guided mode resonances influence the performance of nonlinear metasurfaces. Here we investigate the modal impact on difference-frequency generation in a waveguide-coupledmetasurface platform. The system is constructed fromgold split-ring resonators on a high-indexTiO2 waveguide. We find that a symmetric configuration of the metasurface's localized modes and the extended waveguide modes lead to a modest enhancement of the downconversion process. However, when the mirror symmetry of the localized modes with respect to the guided mode propagation breaks, it introduces external chirality. This enables coupling to a higher quality mode, resulting in a 70-fold enhancement of the difference-frequency generation. The capacity to manipulate the nonlocal modes through the design offers broader control over the interaction and new avenues to tailor the nonlinear processes.

Original languageEnglish
Pages (from-to)1241-1244
Number of pages4
JournalOptics Letters
Issue number5
StatePublished - 1 Mar 2024


FundersFunder number
Israel Science Foundation581/19


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