title: Direct near-field optical imaging of plasmonic resonances in metal nanoparticle pairs.
abstract: In this paper we investigate the near-field optical behavior of plasmon coupling in gold nanoparticle pairs. In particular, by performing series measurements through a fiber-collection mode near-field scanning optical microscope (NSOM), we directly observed the localized electromagnetic (EM) field distribution between two nanospheres is sensitively depended on the incident polarization and interparticle distance. The qualitative near-field observation and quantitative analysis facilitate more understanding of localized hot spots in surface-enhanced Raman scattering (SERS), and nano-applications in selectively controlling the spatial distribution of localized surface plasmon (SP) modes on a fabricated nanostructure by adjusting the polarization direction.
authors.affiliation: Institute of Biomedical Engineering, National Cheng Kung University, No.1, University Road, Tainan 701, Taiwan.
authors.forename: Hsing-Ying
authors.initials: HY
authors.lastname: Lin
authors.forename: Chen-Han
authors.initials: CH
authors.lastname: Huang
authors.forename: Chih-Han
authors.initials: CH
authors.lastname: Chang
authors.forename: Yun-Chiang
authors.initials: YC
authors.lastname: Lan
authors.forename: Hsiang-Chen
authors.initials: HC
authors.lastname: Chui
mesh_terms: D008027:Light; D018625:Microscopy, Atomic Force / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000379:methods*