Dresden 2011 – scientific programme

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MO: Fachverband Molekülphysik

MO 17: Quantum Control

MO 17.6: Talk

Wednesday, March 16, 2011, 17:45–18:00, TOE 317

Efficient and robust strong-field control of populationtransfer in sensitizer dyes with designed femtosecond laser pulses — Johannes Schneider, •Matthias Wollenhaupt, Andreas Winzenburg, Tim Bayer, Jens Köhler, Rüdiger Faust, and Thomas Baumert — University of Kassel, Institute of Physics and CINSaT, D-34132 Kassel, Germany

We demonstrate control of electronic population transfer in molecules with the help of shaped femtosecond laser pulses. To that end we investigate two photosensitizer dyes in solution being prepared in the triplet ground state. Excitation within the triplet system is followed by intersystem crossing and the corresponding singlet fluorescence is monitored as a measure of population transfer in the triplet system. We record control landscapes with respect to the fluorescence intensity on both dyes by a systematic variation of laser pulse shapes combining second order and third order dispersion. In the strong-field regime we find highly structured topologies with large areas of maximum or minimum population transfer being robust with respect to the applied laser intensities. We then compare our experimental results with simulations on generic molecular potentials by solving the TDSE for excitation with shaped pulses. The analysis of the regions of maximum or minimum population transfer reveals that coherent processes control the outcome of the excitation process. The physical mechanisms of joint motion of ground and excited state wave packets or population of an vibrational eigenstate in the excited state permits us to discuss the molecular dynamics in an atom-like picture.