Hannover 2003 – scientific programme

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A: Atomphysik

A 21: Ultraschnelle Ph
änomene + Spektroskopie 2

A 21.2: Talk

Friday, March 28, 2003, 14:15–14:30, F128

Control of Interferences: Symmetry of Control Parameters — •Matthias Wollenhaupt, Andreas Assion, Oksana Bazhan, Christian Horn, Dirk Liese, Christian Sarpe-Tudoran, Marc Winter, and Thomas Baumert — Universität Kassel, Fachbereich Physik, Heinrich-Plett-Str. 40, D-34132 Kassel

Coherent control beyond population control and spectral interferences is demonstrated on the interferences and intensity of the two Autler-Townes (AT) components in the photoelectron spectrum of K atoms using a sequence of two intense time delayed femtosecond laser pulses. Photoelectron spectra were taken at various delay times between the two laser pulses and at different laser intensities at a fixed delay time. With respect to the interferences in the AT doublet the role of time delay and the laser intensity is interchangeable for (n+0.5)π excitation. Strong laser fields or the optical phase of the delayed laser pulse allow the quantum mechanical phase of an atomic state to be manipulated in a symmetrical fashion. The observations are discussed in terms of a two level model coupled to the continuum. For suitable combinations of the laser intensity of the first pulse and the time delay, the second laser pulse leaves the excited state population unchanged.