Directivity enhanced raman spectroscopy using nanoantennas

Aftab Ahmed, Reuven Gordon

Research output: Contribution to journalArticlepeer-review

86 Scopus citations

Abstract

Directing the emission from optical emitters is highly desired for efficient detection and, by reciprocity, efficient excitation as well. As a scattering process, Raman benefits from directivity enhancements in both excitation and emission. Here we demonstrate directivity enhanced Raman scattering (DERS) using a nanoantenna fabricated by focused ion beam milling. The nanoantenna uses a resonant ring-reflector to shape the emitted beam and achieve DERS-this configuration is most similar to a waveguide antenna. The ring reflector boosts the measured Raman signal by a factor of 5.5 (as compared to the ground plane alone), and these findings are in quantitative agreement with comprehensive numerical simulations. The present design is nearly optimal in the sense that almost all the beam power is coupled into the numerical aperture of the microscope. Furthermore, the emission is directed out of the plane, so that this design can be used to achieve DERS using conventional Raman microscopes, which has yet to be achieved with Yagi-Uda and traveling wave antenna designs.

Original languageEnglish (US)
Pages (from-to)1800-1803
Number of pages4
JournalNano letters
Volume11
Issue number4
DOIs
StatePublished - Apr 13 2011
Externally publishedYes

Keywords

  • directivity
  • nanoantennas
  • optical antennas
  • Plasmonics
  • Raman scattering

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