Enhanced nonlinear light generation in oligomers of silicon nanoparticles under vector beam illumination

Maria K. Kroychuk, Alexander S. Shorokhov, Damir F. Yagudin, Daniil A. Shilkin, Daria A. Smirnova, Irina Volkovskaya, Maxim R. Shcherbakov, Gennady Shvets, Andrey A. Fedyanin*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    42 Citations (Scopus)

    Abstract

    All-dielectric nanoparticle oligomers have recently emerged as promising candidates for nonlinear optical applications. Their highly resonant collective modes, however, are difficult to access by linearly polarized beams due to symmetry restraints. In this paper, we propose a new way to increase the efficiency of nonlinear processes in all-dielectric oligomers by tightly focused azimuthally polarized cylindrical vector beam illumination. We demonstrate two orders enhancement of the third-harmonic generation signal, governed by a collective optical mode represented by out-of-plane magnetic dipoles. Crucially, the collective mode is characterized by strong electromagnetic field localization in the bulk of the nonlinear material. For comparison, we measure third-harmonic generation in the same oligomer pumped with linearly and radially polarized fundamental beams, which both show significantly lower harmonic output. We also provide numerical analysis to describe and characterize the observed effect. Our findings open a new route to enhance and modulate the third-harmonic generation efficiency of Mie-resonant isolated nanostructures by tailoring the polarization of the pump beam.

    Original languageEnglish
    Pages (from-to)3471-3477
    Number of pages7
    JournalNano Letters
    Volume20
    Issue number5
    DOIs
    Publication statusPublished - 13 May 2020

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