title: Evaluation of a femtosecond fiber laser for two-photon fluorescence correlation spectroscopy.
abstract: This work evaluates a femtosecond fiber laser for use in two-photon fluorescence fluctuation spectroscopy. Fiber lasers present an attractive alternative to Ti:Sapphire systems because of their compact size and portability. Autocorrelation of the second harmonic generation signal from the laser demonstrates that its stability is sufficient for two-photon fluorescence correlation spectroscopy. Fluorescence correlation spectroscopy autocorrelation traces were well fit by a Gaussian-Lorentzian squared model with a beam waist near the diffraction limit for the 810 nm wavelength. A photon counting histogram collected with this system also fit nicely to a single-species model, further demonstrating the quality of the focal shape. The authors conclude that the output from the femtosecond fiber laser is sufficiently stable and has a high enough quality beam shape for fluctuation fluorescence methods, and thus represents an effective, compact, readily portable two-photon excitation source.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
authors.forename: Jay R
authors.initials: JR
authors.lastname: Unruh
authors.forename: E Shane
authors.initials: ES
authors.lastname: Price
authors.forename: Roque G
authors.initials: RG
authors.lastname: Molla
authors.forename: Rongqing
authors.initials: R
authors.lastname: Hui
authors.forename: Carey K
authors.initials: CK
authors.lastname: Johnson