Control of the plasmonic near-field in metallic nanohelices

Jose M. Caridad, Sinead Winters, David McCloskey, Georg S. Duesberg, John F. Donegan, Vojislav Krstic*

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    The optical response of metallic nanohelices is mainly governed by a longitudinal localised surface plasmon resonance (LSPR) which arises due to the helical anisotropy of the system. Up to now, experimental studies have predominantly addressed the far-field response, despite the fact that the LSPR being of broad interest for converting incoming light into strongly enhanced (chiral) optical near-fields. Here, we demonstrate the control and spatial reproducibility of the plasmon-induced electromagnetic near-field around metallic nanohelices via surface-enhanced Raman scattering. We discuss how the near-field intensity of these nanostructures can be custom-tailored through both the nanoscaled helical structure and the electronic properties of the constituting metals. Our experiments, which employ graphene as an accurate probing material, are in quantitative agreement with corresponding numerical simulations. The findings demonstrate metallic nanohelices as reference nanostructured surfaces able to provide and fine-tune optical fields for fundamental studies as well as sensing or (chiro-optical) imaging applications.
    Original languageEnglish
    Article number325204
    JournalNanotechnology
    Volume29
    Issue number32
    Number of pages6
    ISSN0957-4484
    DOIs
    Publication statusPublished - 2018

    Keywords

    • Optical helical antennae
    • Chiro-optical plasmon
    • Near-field
    • Helical nanostructure
    • Graphene
    • SERS
    • Nanostructured thin films

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