Optical field imaging of elongated rectangular nanovoids in gold thin film

Kohei Imura, Kosei Ueno, Hiroaki Misawa, Hiromi Okamoto

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    We studied optical properties of single elongated rectangular nanovoids opened on a thin gold film by scanning near-field optical microscopy. We found that the luminescence is induced via two-photon absorption of near-infrared pulses when the sample is locally photoexcited inside the void as well as on the film. The luminescence spectrum of the void shows spectral features very similar to those observed for gold nanorods and is attributable to that from gold. On the basis of the near-field two-photon excitation imaging by detecting the luminescence, we visualized the optical fields near the voids. The optical image shows a characteristic spatial feature depending on the dimension of the void. From the close inspection of the topography and the optical images, we found that excitation probability becomes high at the metal-void boundary as well as inside the void. We found an oscillating feature along the long axis of the void. The observed spatial features were qualitatively reproduced by photonic local density-of-states based on electromagnetic calculations, and we concluded that the oscillation observed inside the void is attributed to the electromagnetic modes in the void coupled with the plasmon excitations.

    Original languageEnglish
    Pages (from-to)2449-2454
    Number of pages6
    JournalJournal of Physical Chemistry C
    Volume117
    Issue number6
    DOIs
    Publication statusPublished - 2013 Feb 14

    Fingerprint

    Gold
    Luminescence
    voids
    gold
    Imaging techniques
    Thin films
    Photons
    thin films
    Near field scanning optical microscopy
    Nanorods
    Photonics
    Topography
    near fields
    Optical properties
    Inspection
    Metals
    luminescence
    Infrared radiation
    electromagnetism
    excitation

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Electronic, Optical and Magnetic Materials
    • Surfaces, Coatings and Films
    • Energy(all)

    Cite this

    Optical field imaging of elongated rectangular nanovoids in gold thin film. / Imura, Kohei; Ueno, Kosei; Misawa, Hiroaki; Okamoto, Hiromi.

    In: Journal of Physical Chemistry C, Vol. 117, No. 6, 14.02.2013, p. 2449-2454.

    Research output: Contribution to journalArticle

    Imura, Kohei ; Ueno, Kosei ; Misawa, Hiroaki ; Okamoto, Hiromi. / Optical field imaging of elongated rectangular nanovoids in gold thin film. In: Journal of Physical Chemistry C. 2013 ; Vol. 117, No. 6. pp. 2449-2454.
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