Open AccessNear-field coupling of a single fluorescent molecule and a spherical gold nanoparticle
Author(s) -
Thomas Härtling,
Philipp Reichenbach,
Lukas M. Eng
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.012806
Subject(s) - fluorophore , materials science , fluorescence , total internal reflection fluorescence microscope , optics , molecular physics , microscopy , scattering , absorption (acoustics) , near and far field , nanoparticle , excitation , quantum yield , dipole , fluorescence correlation spectroscopy , nanotechnology , chemistry , physics , organic chemistry , quantum mechanics , composite material
Near-field coupling of a single gold nanoparticle (GNP) to a single fluorescent molecule is investigated here for varying separation d between the two. While the emission quantum efficiency of the coupled system generally decreases for d!0, a pronounced near-field enhancement is observed under certain conditions, partly outweighing the efficiency loss at small distances. We report on optimizing these conditions by varying the excitation field direction and the three-dimensional relative configuration between the GNP and the fluorophore. Furthermore, we examine how the sphere diameter, the surrounding medium, as well as the absorption and emission wavelengths of the molecular dipole influence the fluorescence yield. Our results are of high practical relevance for all GNP-mediated application fields such as fluorescence microscopy, scattering near-field optical microscopy, bioanalytics, and medical applications.