title: Quantitative differentiation of dyes with overlapping one-photon spectra by femtosecond pulse shaping.
abstract: We demonstrate that DiI and Rhodamine B, which are not easily distinguishable to one-photon measurements, can be differentiated and in fact quantified in mixture via tailored two-photon excitation pulses found by a genetic algorithm (GA). A nearly three-fold difference in the ratio of two-photon fluorescence of the two dyes is achieved, without a drop in signal of the favored fluorophore. Implementing an acousto-optic interferometer, we were able to prove that the mechanism of discrimination is second-harmonic tuning by the phase-shaped pulses to the relative maxima and minima of these cross-sections.
authors.affiliation: Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, MI 48109-2099, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Tkaczyk
authors.forename: Alan H
authors.initials: AH
authors.lastname: Tkaczyk
authors.forename: Koit
authors.initials: K
authors.lastname: Mauring
authors.forename: Jing Yong
authors.initials: JY
authors.lastname: Ye
authors.forename: James R
authors.initials: JR
authors.lastname: Baker
authors.forename: Theodore B
authors.initials: TB
authors.lastname: Norris