Authors
Davy Gérard, Alexis Devilez, Heykel Aouani, Brian Stout, Nicolas Bonod, Jérome Wenger, Evgueny Popov, Hervé Rigneault,
Title
Efficient excitation and collection of single-molecule fluorescence close to a dielectric microsphere
In
Journal of the Optical Society of America B, Optical physics
Volume
26
Issue
7
Pages
1473–1478
Publisher
OSA
Year
2009
Publisher's URL
http://www.opticsinfobase.org/josab/abstract.cfm?uri=josab-26-7-1473
Indexed by
Abstract
Dielectric microspheres illuminated by a tightly focused Gaussian beam can focus light on a tiny spot with subwavelength dimensions along the three directions of space. We report here a detailed experimental and theoretical study of the interaction between a single fluorescent molecule and this peculiar electromagnetic distribution. The microsphere increases the excitation intensity sensed by the molecule up to a factor of 2.2, while at the same time it allows for a collection efficiency of up to 60% by redirecting the light emitted at large incidences toward the optical axis. By combining these two effects, the number of collected fluorescence photons can be increased up to a factor of 5. We quantify the evolution of the excitation and collection contributions with the microsphere dimensions and compare our experimental findings with numerical simulations.
Affiliations
Offprint