Abstract

A fluorescence correlation spectroscopy experiment that combines two-photon excitation and a standing-wave interference pattern is presented. The experimental correlation function can be analyzed using a simple expression involving (1) an exponential decay with time constant ${\tau }_f$, which reflects diffusion across the interference fringes, and (2) a longer-lived decay with time constant ${\tau }_{\omega }$, which reflects diffusion in and out of the focal spot. The diffusion of Rhodamine 110 in water and ethylene glycol is measured using this method. The ability to simultaneously measure diffusion on two different time and lengthscales makes this experiment especially useful in environments where anomalous diffusion is suspected.

© 2007 Optical Society of America

Two-photon standing-wave fluorescence correlation spectroscopy: erratum

Kerry M. Hanson, Sara K. Davis, and Christopher J. Bardeen
Opt. Lett. 32(22) 3308-3308 (2007)

Excitation saturation in two-photon fluorescence correlation spectroscopy

Keith Berland and Guoqing Shen
Appl. Opt. 42(27) 5566-5576 (2003)

Lorentzian spatial intensity distribution in one-photon fluorescence correlation spectroscopy

Hans Blom and Gunnar Björk
Appl. Opt. 48(31) 6050-6058 (2009)

Two-photon fluorescence correlation spectroscopy through a dual-clad optical fiber

Yu-Chung Chang, Jing Yong Ye, Thommey Thomas, Yi Chen, James R. Baker, and Theodore B. Norris
Opt. Express 16(17) 12640-12649 (2008)

Fast two-dimensional standing-wave total-internal-reflection fluorescence microscopy using acousto-optic deflectors

Olga Gliko, William E. Brownell, and Peter Saggau
Opt. Lett. 34(6) 836-838 (2009)