Coherent control of two photon fluorescence with a high-resolution spectral phase shaper

We present effects of spectral shaping on the two-photon fluorescence from fluorescent dye molecules in solution and from quantum dots. The experiments are done with sub-25 fs pulses around 800 nm and a compact (7×10 cm2) high resolution reflective spectral phase shaper. Our results demonstrate that the sign of a phase step in the spectrum of the excitation pulses influences the amount of fluorescence. This implies that beside the two-photon spectral intensity the phase of this spectrum is important as well.