《Spectral dependence of single molecule》.pdf

Spectral dependence of single molecule fluorescence enhancement Palash Bharadwaj and Lukas Novotny Institute of Optics and Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627, USA novotny@optics.rochester.edu Abstract: The fluorescence from a single molecule can be strongly enhanced near a metal nanoparticle acting as an optical antenna. We demonstrate the spectral tunability of this antenna effect and show that maximum enhancement is achieved when the emission frequency is red-shifted from the surface plasmon resonance of the particle. Our experi- mental results, using individual gold and silver particles excited at different laser-frequencies, are in good agreement with an analytical theory which predicts a different spectral dependence of the radiative and non-radiative decay rates. © 2007 Optical Society of America OCIS codes: (260.2510) Fluorescence; (260.2160) Energy transfer; (160.4236) Nanomaterials; (240.6680) Surface plasmons. References and links 1. P. Anger, P. Bharadwaj, and L. Novotny, “Enhancement and quenching of single-molecule fluorescence,” Phys. Rev. Lett. 96, 113002 (2006). 2. S. K¨uhn, S. U. H˚akanson, L. Rogobete, and V. Sandoghdar, “Enhancement of single-molecule fluorescence using a gold nanoparticle as an optical nanoantenna,” Phys. Rev. Lett. 97, 017402 (2006). 3. J. N. Farahani, D. W. Pohl, H.-J. Eisler, and B. Hecht, “Single quantum dot coupled to a scanning optical antenna: a tunable superemitter,” Phys. Rev. Let