Europhys. Lett., 69 (4), pp. 538-543 (2005)
DOI: 10.1209/epl/i2004-10388-9

Optical near-field of multipolar plasmons of rod-shaped gold nanoparticles

A. Hohenau¹, J. R. Krenn¹, G. Schider¹, H. Ditlbacher¹, A. Leitner¹, F. R. Aussenegg¹ and W. L. Schaich<sup>2

1</sup>  Institute for Experimental Physics and Erwin Schrödinger Institute for Nanoscale Research, Karl-Franzens-University Graz - A-8010 Graz, Austria
²  Department of Physics, Indiana University - Bloomington, IN 47405, USA

received 30 August 2004; accepted in final form 10 December 2004
published online 19 January 2005

Abstract
We report on near-field measurements and calculations of the optical intensity close to rod-shaped gold nanoparticles excited at a multipolar plasmon resonance. Our results reveal a distinct optical near-field pattern and show that multipolar plasmon excitation of single nanoparticles can be imaged in the near-field. The observed optical near-field patterns can be understood in a model of standing plasmon waves.

PACS
42.25.Hz - Wave optics: Interference.
73.20.Mf - Collective excitations (including excitons, polarons, plasmons and other charge-density excitations).
78.67.Bf - Optical properties of bulk materials and thin films: Nanocrystals and nanoparticles.

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