Open AccessSurface plasmon-enhanced and quenched two-photon excited fluorescence
Author(s) -
Chun Yu Lin,
KueiChen Chiu,
Chia Yuan Chang,
ShunPing Chang,
Tzung Fang Guo,
Shean Jen Chen
Publication year - 2010
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.18.012807
Subject(s) - total internal reflection fluorescence microscope , fluorescence in the life sciences , fluorescence , materials science , surface plasmon , quantum yield , excited state , resonance fluorescence , total internal reflection , fluorophore , optics , fluorescence correlation spectroscopy , plasmon , optoelectronics , atomic physics , physics
This study investigated theoretically and experimentally that two-photon excited fluorescence is enhanced and quenched via surface plasmons (SPs) excited by total internal reflection with a silver film. The fluorescence intensity is fundamentally affected by the local electromagnetic field enhancement and the quantum yield change according to the surrounding structure and materials. By utilizing the Fresnel equation and classical dipole radiation modeling, local electric field enhancement, fluorescence quantum yield, and fluorescence emission coupling yield via SPs were theoretically analyzed at different dielectric spacer thicknesses between the fluorescence dye and the metal film. The fluorescence lifetime was also decreased substantially via the quenching effect. A two-photon excited total internal reflection fluorescence (TIRF) microscopy with a time-correlated single photon counting device has been developed to measure the fluorescence lifetimes, photostabilities, and enhancements. The experimental results demonstrate that the fluorescence lifetimes and the trend of the enhancements are consistent with the theoretical analysis. The maximum fluorescence enhancement factor in the surface plasmon-total internal reflection fluorescence (SP-TIRF) configuration can be increased up to 30 fold with a suitable thickness SiO(2) spacer. Also, to compromise for the fluorescence enhancement and the fluorophore photostability, we find that the SP-TIRF configuration with a 10 nm SiO(2) spacer can provide an enhanced and less photobleached fluorescent signal via the assistance of enhanced local electromagnetic field and quenched fluorescence lifetime, respectively.