Power spectral analysis for evaluating optical near-field images of 20 nm gold particles

Rajagopalan Umamaheswari, H. Kadono, M. Ohtsu

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

We have demonstrated that the power spectral analysis could be employed as a potential tool for evaluation of near-field optical images of colloidal gold particles of size 20 nm fixed on a glass substrate. It has been found that the power spectral density of the near-field image resembles the Airy pattern due to a circular dot with the first minimum occurring at the spatial frequency 5.6 × 107 m-1. This corresponds to an estimated particle diameter of 22 nm. From a comparison with the theoretical power spectral density of randomly distributed circular dots, the transfer function of the near-field optical microscope has been estimated. It has been found that the resolution estimated using -3 dB cutoff value obtained from the transfer function was 0.8 nm which is much higher than that determined by aperture size. The high resolving ability of the present microscopic system is believed to be due to the confinement of very high spatial frequency evanescent fields around the edges of the metal-glass fiber boundary at the apex of the apertured probe.

Original languageEnglish
Pages (from-to)133-142
Number of pages10
JournalOptics Communications
Volume131
Issue number1-3
DOIs
Publication statusPublished - 1996 Oct 15
Externally publishedYes

Fingerprint

Power spectral density
Gold
Spectrum analysis
spectrum analysis
Transfer functions
near fields
gold
Evanescent fields
Gold Colloid
transfer functions
Glass fibers
metal fibers
Microscopes
Metals
glass fibers
optical microscopes
Glass
apexes
Substrates
cut-off

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

Cite this

Power spectral analysis for evaluating optical near-field images of 20 nm gold particles. / Umamaheswari, Rajagopalan; Kadono, H.; Ohtsu, M.

In: Optics Communications, Vol. 131, No. 1-3, 15.10.1996, p. 133-142.

Research output: Contribution to journalArticle

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