Near-field surface plasmon field enhancement induced by rippled surfaces

Year: 2017

Authors: D’Acunto M., Fuso F., Micheletto R., Naruse M., Tantussi F., Allegrini M.

Autors Affiliation: CNR, ISM, Via Fosso Cavaliere 100, I-00133 Rome, Italy; CNR, Ist Biofis, IBF, Via Moruzzi 1, I-56124 Pisa, Italy;‎ Univ Pisa, Dipartimento Fis Enrico Fermi, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy;‎ Univ Pisa, CNISM, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy; CNR, INO, Via Moruzzi 1, I-56124 Pisa, Italy; Yokohama City Univ, Grad Sch Nanobiosci, Kanazawa Ku, 22-2 Seto, Yokohama, Kanagawa, Japan; Harvard Med Sch, 64 Sydney St,Suite 170, Cambridge, MA 02139 USA;‎ Natl Inst Informat & Commun Technol, Network Syst Res Inst, 4-2-1 Nukui Kita, Koganei, Tokyo 1848795, Japan

Abstract: The occurrence of plasmon resonances on metallic nanometer-scale structures is an intrinsically nanoscale phenomenon, given that the two resonance conditions (i.e., negative dielectric permittivity and large free-space wavelength in comparison with system dimensions) are realized at the same time on the nanoscale. Resonances on surface metallic nanostructures are often experimentally found by probing the structures under investigation with radiation of various frequencies following a trial-and-error method. A general technique for the tuning of these resonances is highly desirable. In this paper we address the issue of the role of local surface patterns in the tuning of these resonances as a function of wavelength and electric field polarization. The effect of nanoscale roughness on the surface plasmon polaritons of randomly patterned gold films is numerically investigated. The field enhancement and relation to specific roughness patterns is analyzed, producing many different realizations of rippled surfaces. We demonstrate that irregular patterns act as metal-dielectric-metal local nanogaps (cavities) for the resonant plasmonic field. In turn, the numerical results are compared to experimental data obtained via aperture scanning near-field optical microscopy.


Volume: 8      Pages from: 956  to: 967

KeyWords: aperture scanning near-field optical microscopy; gold rippled surface; localized hot spots; metal-dielectric-metal nanogaps; surface plasmon resonance
DOI: 10.3762/bjnano.8.97

Citations: 6
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