title: Double-resonant enhancement of third-harmonic generation in graphene nanostructures.
abstract: Intriguing and unusual physical properties of graphene offer remarkable potential for advanced, photonics-related technological applications, particularly in the area of nonlinear optics at the deep-subwavelength scale. In this study, we use a recently developed numerical method to illustrate an efficient mechanism that can lead to orders of magnitude enhancement of the third-harmonic generation in graphene diffraction gratings. In particular, we demonstrate that by taking advantage of the geometry dependence of the resonance wavelength of localized surface-plasmon polaritons of graphene ribbons and discs one can engineer the spectral response of graphene gratings so that strong plasmonic resonances exist at both the fundamental frequency and third-harmonic (TH). As a result of this double-resonant mechanism for optical near-field enhancement, the intensity of the TH can be increased by more than six orders of magnitude.This article is part of the themed issue 'New horizons for nanophotonics'.
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
authors.forename: Jian Wei
authors.initials: JW
authors.lastname: You
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
authors.forename: Jie
authors.initials: J
authors.lastname: You
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Weismann
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK n.panoiu@ucl.ac.uk.
authors.forename: Nicolae C
authors.identifier: http://orcid.org/0000-0001-5666-2116
authors.initials: NC
authors.lastname: Panoiu
keywords: graphene; plasmons; third-harmonic generation