Mapping plasmonic near-field profiles and interferences by surface-enhanced Raman scattering
Lei, Dang Yuan
Maier, Stefan A.
Date of Issue2013
School of Electrical and Electronic Engineering
Mapping near-field profiles and dynamics of surface plasmon polaritons is crucial for understanding their fundamental optical properties and designing miniaturized photonic devices. This requires a spatial resolution on the sub-wavelength scale because the effective polariton wavelength is shorter than free-space excitation wavelengths. Here by combining total internal reflection excitation with surface-enhanced Raman scattering imaging, we mapped at the sub-wavelength scale the spatial distribution of the dominant perpendicular component of surface plasmon fields in a metal nanoparticle-film system through spectrally selective and polarization-resolved excitation of the vertical gap mode. The lateral field-extension at the junction, which is determined by the gap-mode volume, is small enough to distinguish a spot size ~0.355λ0 generated by a focused radially polarized beam with high reproducibility. The same excitation and imaging schemes are also used to trace near-field nano-focusing and interferences of surface plasmon polaritons created by a variety of plasmon lenses.
DRNTU::Engineering::Electrical and electronic engineering
© 2013 The Authors. This paper was published in Scientific Reports and is made available as an electronic reprint (preprint) with permission of the authors. The paper can be found at the following official DOI: [http://dx.doi.org/10.1038/srep03064]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.