Adiabatic nanofocusing scattering-type optical nanoscopy of individual gold nanoparticles

Nano Lett. 2011 Apr 13;11(4):1609-13. doi: 10.1021/nl1045457. Epub 2011 Mar 22.

Abstract

We explore imaging of local electromagnetic fields in the vicinity of metallic nanoparticles using a grating-coupled scattering-type near-field scanning optical microscope. In this microscope, propagating surface plasmon polariton wavepackets are launched onto smooth gold tapers where they are adiabatically focused toward the nanometer-sized taper apex. We report two-dimensional raster-scanned optical images showing pronounced near-field contrast and demonstrating sub-30 nm resolution imaging of localized surface plasmon polariton fields of spherical and elliptical nanoparticles. By comparison to three-dimensional finite-difference time domain simulations, we conclude that virtually background-free near-field imaging is achieved. The microscope combines deep subwavelength resolution, high local field intensities and a straightforward imaging contrast, making it interesting for a variety of applications in linear and nonlinear nanospectroscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gold / chemistry*
  • Image Enhancement / methods*
  • Materials Testing / methods
  • Microscopy, Scanning Probe / methods*
  • Molecular Conformation
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Particle Size
  • Surface Properties

Substances

  • Gold