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

    Fingerprint

    Metal nanoparticles
    assemblies
    Spatial distribution
    spatial distribution
    nanoparticles
    metals
    dipoles
    rims
    Nanospheres
    Gold
    excitation
    near fields
    Photons
    interactions
    gold
    Infrared radiation
    propagation
    causes
    photons

    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)

    Cite this

    Spatial distribution of enhanced optical fields in monolayered assemblies of metal nanoparticles : Effects of interparticle coupling. / Okamoto, Hiromi; Imura, Kohei; Shimada, Toru; Kitajima, Masahiro.

    In: Journal of Photochemistry and Photobiology A: Chemistry, Vol. 221, No. 2-3, 25.06.2011, p. 154-159.

    Research output: Contribution to journalArticle

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