Spatio-temporal dynamics of plasmons on a metal cone

ORAL

Abstract

Localized surface plasmons (LSP) and propagating plasmon modes (PPM) field emit at the singularity of the metallic tip apex upon ultrafast optical excitation. Interferometric measurements, using frequency modulation-demodulation techniques, allow the characterization of the time profile of the optical field emission and the space-time profile of the propagating modes. A pump pulse launches a plasmon that oscillates on the cone and coherently interferes with a time-delayed probe pulse which is cross-polarized with respect to the pump. We present a simple model that accurately describes the experimental results. However, the observations of trapped propagating modes, their lifetime, and their polarization are not predicted by current theories, which describe tip-plasmons as strictly transverse magnetic modes.

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Authors

  • Alejandro Rodriguez Perez

    Department of Chemistry, University of California, Irvine, University of California, Irvine

  • Joonhee Lee

    Department of Chemistry, University of California, Irvine, University of California, Irvine

  • Shawn M. Perdue

    Department of Chemistry, University of California, Irvine, University of California, Irvine

  • V. Ara Apkarian

    Department of Chemistry, University of California, Irvine, University of California, Irvine