Plasmonic focusing on a tip for spectroscopic nano-imaging

ORAL

Abstract

The focusing of light into sub-diffraction limit dimensions has been a long-standing challenge in imaging and spectroscopy. Here, we study the adiabatic concentration of propagating surface plasmon polaritons on a tapered metal tip into a localized and enhanced nanoscale excitation at the apex. Using far-field spectroscopic characterization and near-field imaging we demonstrate spatial confinement of the radially symmetric TM mode (m = 0) to within just several 10s of nm as determined by the apex radius. Ultrahigh spatial resolution near-field Raman and luminescence imaging is demonstrated with enhanced sensitivity and minimal far-field background.

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Authors

  • Samuel Berweger

    • University of Washington, Departments of Chemistry and Physics

  • Catalin C. Neacsu

    • University of Washington, Departments of Chemistry and Physics

  • Robert L. Olmon

    • University of Washington, Departments of Chemistry and Physics

  • Laxmikant V. Saraf

    • Pacific Northwest National Laboratory

  • Claus Ropers

    • Courant Research Center, University of G\"ottingen, Germany

  • Markus B. Raschke

    • University of Washington Departments of Chemistry and Physics
    • University of Washington, Seattle
    • University of Washington, Departments of Chemistry and Physics
    • Departments of Chemisty and Physics, University of Washington