Biomedical Engineering Reference
In-Depth Information
Chapter 12
Probing Magnetic Plasmons with Vortex
Electron Beams
Reuven Gordon
Department of Electrical and Computer Engineering, University of Victoria,
Victoria, BC V8P5C2, Canada
rgordon@uvic.ca
12.1 Introduction
Recent advances in nanotechnology have inspired researchers to
search for artificial materials with any desired optical response. Of
particular interest are materials with negative refraction, which al-
lowsforperfectlensing(Pendry,2000).Negativerefractionrequires
both negative permittivity and permeability. Such a response can be
achieved by nanostructuring metals and dielectrics at a scale much
smaller than the optical wavelength (Smith et al., 2004). Indeed,
the approach of metamaterials is to create extreme subwavelength
features that have a strong response, and usually this means a
resonance, in the frequency range of interest.
The question arises: how can we achieve strong electric and
magnetic resonances in the visible regime? To help answer this
