title: Visualization of localized intense optical fields in single gold-nanoparticle assemblies and ultrasensitive Raman active sites.
abstract: We demonstrate visualization of localized intense electromagnetic fields in real space in well-tailored dimeric and trimeric gold nanospheres by using near-field optical techniques. With two-photon induced luminescence and Raman measurements, we show that the electric field is confined at an interstitial site in the aggregate. We also demonstrate optical switching operations for the electric-field localized sites in the trimer structure.
authors.affiliation: Institute for Molecular Science and The Graduate University for Advanced Studies, Okazaki, Aichi 444-8585, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Imura
authors.forename: Hiromi
authors.initials: H
authors.lastname: Okamoto
authors.forename: Mohammad K
authors.initials: MK
authors.lastname: Hossain
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kitajima
mesh_terms: D004574:Electromagnetic Fields; D006046:Gold / Q000737:chemistry*; D007089:Image Enhancement / Q000379:methods*; D008027:Light; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D006046:Gold