Low-Power Photothermal Probing of Single Plasmonic Nanostructures with Nanomechanical String Resonators

Silvan Schmid, Kaiyu Wu, Peter Emil Larsen, Tomas Rindzevicius, Anja Boisen

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    Abstract

    We demonstrate the direct photothermal probing and mapping of single plasmonic nanostructures via the temperature-induced detuning of nanomechanical string resonators. Single Au nanoslits and nanorods are illuminated with a partially polarized focused laser beam (λ = 633 nm) with irradiances in the range of 0.26–38 μW/μm2. Photothermal heating maps with a resolution of ∼375 nm are obtained by scanning the laser over the nanostructures. Based on the string sensitivities, absorption efficiencies of 2.3 ± 0.3 and 1.1 ± 0.7 are extracted for a single nanoslit (53 nm × 1 μm) and nanorod (75 nm × 185 nm). Our results show that nanomechanical resonators are a unique and robust analysis tool for the low-power investigation of thermoplasmonic effects in plasmonic hot spots.
    Original languageEnglish
    JournalNano Letters
    Volume14
    Issue number5
    Pages (from-to)2318-2321
    ISSN1530-6984
    DOIs
    Publication statusPublished - 2014

    Keywords

    • Plasmonic hot spots
    • Thermoplasmonics
    • Nanomechanical resonators
    • Optical heating
    • Photothermal mapping

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