Scanning Near-Field Infared Microscopy and Spectroscopy with a Broadband Laser Source

Published

October 1, 2000

Author(s)

Chris A. Michaels, Lee J. Richter, Richard R. Cavanagh, Stephan J. Stranick

Abstract

Near-field scanning optical microscopy (NSOM) is a powerful tool for the characterization of the optical properties of nanoscale objects, although pervasive artifacts often create difficulties in image interpretation. A three dimensional scanning NSOM method that yields artifact-free, constant height mode (CHM) images is discussed. A set of λ = 488 nm, CHM images of a Au nanoparticle sample acquired at probe-sample separations varying from 7 ± 3 nm to 160 ± 3 nm are presented. Analysis of optical features due to scattering from a Au nanoparticle provides an experimental measure of the spatial resolution decay as the sample is moved from the near-field of the probe aperture toward the far-field. The spatial resolution decays slowly for probe-sample separations up to approximately 110 nm, beyond which it quickly approaches the far-field diffraction limit.

Citation

Journal of Applied Physics

Volume

88

Issue

No. 8

Pub Type

Journals

Keywords

metal nanoparticles, near-field scanning optical microscopy, NSOM, optical microscopy

Citation

Michaels, C. , Richter, L. , Cavanagh, R. and Stranick, S. (2000), Scanning Near-Field Infared Microscopy and Spectroscopy with a Broadband Laser Source, Journal of Applied Physics (Accessed October 11, 2025)