Surface-plasmon vortices in nanostructured metallic films
A. A. Ezhov, S. A. Magnitskii, N. S. Maslova, D. A. Muzychenko, A. A. Nikulin, V. I. Panov
Department of Physics, M. V. Lomonosov Moscow State University, 119992 Moscow, Russia
PACS: 74.50.+r, 74.80.Fp
Abstract
Light scattering by a small protrusion on a metal
surface is analyzed within the framework of perturbation theory.
Upon normal incidence of linearly-polarized monochromatic wave,
slight deviations of the protrusion shape from a circularly
symmetric one lead to formation of optical vortices in the
near-field region due resonant excitation of circular surface
plasmons. This agrees with the results of scanning near-field
optical microscopy experiments revealing distinct spiral patterns
in the in-plane near-field intensity distribution for metallized
nanostructured polymer substrates.