Visualization of Localized Intense Optical Fields in Single Gold−Nanoparticle Assemblies and Ultrasensitive Raman Active Sites

• Published in: Nano letters Vol. 6; no. 10; pp. 2173 - 2176
• Main Authors: Imura, Kohei, Okamoto, Hiromi, Hossain, Mohammad K, Kitajima, Masahiro
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-10-2006
• Subjects: Cross-disciplinary physics: materials science; rheology; Electromagnetic Fields; Exact sciences and technology; Gold - chemistry; Image Enhancement - methods; Light; Materials science; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology - methods; Particle Size; Physics; Sensitivity and Specificity; Spectrum Analysis, Raman - methods; Gold; Trimer; Interstitials; Luminescence; Electromagnetic fields; Experimental study; Switching; Nanoparticles; SERS; Colloidal suspension; Electric field effects; Transition elements; Topography; Nanosphere; Aggregate; Nanostructured materials
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl061650p

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.