Spatial distribution of enhanced optical fields in monolayered assemblies of metal nanoparticles: Effects of interparticle coupling

Hiromi Okamoto, Kohei Imura, Toru Shimada, Masahiro Kitajima

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Near-field two-photon excitation images of assemblies of many gold nanospheres show characteristic feature that enhanced optical fields are confined at the rim parts of the assemblies. In the present report we analyzed the origin of this feature based on finite-difference time-domain (FDTD) approach as well as a simple point dipole model that incorporates the interparticle interaction with the dipole-dipole potential. It has been found that the simple point dipole model is useful for qualitative discussion on the optical field distribution in the metal nanoparticle assemblies. From the analysis, we have found that the interparticle interaction, which causes the propagation of the plasmon excitation in the assemblies, seems to be essential for the localization of the enhanced field at the rim. We propose that regular close-packed assemblies do not yield efficiently enhanced optical fields in visible to near-infrared region, and rather assemblies with large fluctuation are more advantageous to get highly enhanced fields.

Original languageEnglish
Pages (from-to)154-159
Number of pages6
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume221
Issue number2-3
DOIs
Publication statusPublished - 2011 Jun 25

Keywords

  • Enhanced optical fields
  • Finite-difference time-domain (FDTD) method
  • Metal nanoparticles
  • Near-field optical microscopy
  • Surface enhanced Raman scattering
  • Surface plasmon resonance

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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