Düsseldorf 2007 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 61: Quantum Control I
MO 61.4: Vortrag
Freitag, 23. März 2007, 11:15–11:30, 6F
Coherent Control despite a dominant spectral Continuum: — •Heide Ibrahim1, Mónika Héjjas1, Mizuho Fushitani2, Markus Gühr3, and Nikolaus Schwentner1 — 1FU Berlin, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin — 2Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan — 3Stanford PULSE Center, Varian Physics Bldg., 382 Via Pueblo Mall, Stanford CA 94305-4060, USA
The interaction strength of a vibrational mode with a multidimensional (crystalline) environment is reflected in frequency domain spectroscopy in the lineshape. Weak coupling leads to sharp zero-phonon-lines (ZPL) which represent an exclusive chromophore vibrational excitation. Phonon side bands (PSB) display the simultaneous excitation of bath modes which merge to a continuum with increasing strength. Concerning coherent control of molecular dynamics it is desirable to generate analoguos weakly and strongly coupled vibrational wave packets composed of ZPL or PSB respectively by appropriate femtosecond pulse sequences. The X-A and X-B transitions of Br2 in an Ar matrix provide these properties and are used to develop the means to achieve this separation with phase locked pulses. Firstly we show that the powerful A continuum and the faint B progression can be sorted out by either state-selective fluorescence or an additional probe step. Secondly we illustrate how variably coupled wave packets are generated by optimising timing and phases of pulse sequences. Pros and cons of sequence generation with spatial light modulators or interferometers are analysed based on a Fouriertransformation.