Enhanced Third-Harmonic Generation in Silicon Nanoparticles Driven by Magnetic Response

Abstract

We observe enhanced third-harmonic generation from silicon nanodisks exhibiting both electric and magnetic dipolar resonances. Experimental characterization of the nonlinear optical response through third-harmonic microscopy and spectroscopy reveals that the third-harmonic generation is significantly enhanced in the vicinity of the magnetic dipole resonances. The field localization at the magnetic resonance results in two orders of magnitude enhancement of the harmonic intensity with respect to unstructured bulk silicon with the conversion efficiency limited only by the two-photon absorption in the substrate.

Enhanced second-harmonic generation from magnetic resonance in AlGaAs nanoantennas

“…Even though plasmonic antennas have been employed for many applications, metals suffer from large resistive heating losses in the visible and near-infrared (near-IR) wavelength range, which limit device performance [8,9]. Therefore, several recent works [8][9][10][11][12][13] have focused on a new class of all-dielectric optical nanoantennas. These consist of high-permittivity lowloss dielectric particles of sub-micrometer size.…”

“…Semiconductor nanoparticles are emerging as a promising alternative to metallic ones for a wide range of nanophotonic applications based on localized resonant modes in the entire visible and near-IR spectral ranges, see e.g [8][9][10]. Different particle geometries can be considered, but mainly spherical and cylindrical antennas have been dealt with to date.…”

“…Dielectric nanostructures on a low-index substrate have been recently demonstrated in the framework of semiconductor planar technology, encompassing the cases of silicon on insulator [10], as well as GaAs on silica [12]. All-dielectric nanoantennas offer unique opportunities for the study of nonlinear effects due to very low losses in combination with multipolar characteristics of both electric and magnetic resonant optical modes [10].…”

“…All-dielectric nanoantennas offer unique opportunities for the study of nonlinear effects due to very low losses in combination with multipolar characteristics of both electric and magnetic resonant optical modes [10]. The nonlinear optical effects of magnetic origin can have fundamentally different properties compared with those of electric origin.…”

“…When nonlinearities of both electric and magnetic type are present, the nonlinear response can be substantially modified and is accompanied by nonlinear mode mixing and magnetoelectric coupling [16,17]. To the best of our knowledge, the only investigations of the nonlinear optical response generated from a magnetic resonant optical mode in an all-dielectric antenna have been conducted on Si nanodisks [10,14]. However, in that case, operation in the third window of optical fiber communication is limited by two-photon absorption (TPA) and volume χ (2) interactions are absent because of centrosymmetry of Si.…”