Hamburg 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
A: Fachverband Atomphysik
A 34: Poster II
A 34.36: Poster
Donnerstag, 5. März 2009, 16:30–19:00, VMP 9 Poster
Selective excitation of multiple states in atomic sodium by a single chirped femtosecond laser pulse — Marc Krug1, Svetoslav Ivanov2, Matthias Wollenhaupt1, Tim Bayer1, •Christian Lux1, Nikolay V. Vitanov2, and Thomas Baumert1 — 1Universität Kassel, Institut für Physik und Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Str. 40, D-34132 Kassel, Germany — 2Theoretical Physics Division - Department of Physics, Sofia University - James Bourchier 5 blvd, 1164 Sofia, Bulgaria
Chirped femtosecond laser pulses generated by spectral phase modulation are used for strong-field Resonance Enhanced Multi-Photon Ionization (REMPI) of atomic sodium. Photoelectron Angular Distributions (PADs) are measured employing a photoelectron imaging spectrometer. Pronounced differences in the PADs with respect to the sign of the chirp (up-chirp/down-chirp) are observed experimentally. We identify three contributing ionization processes, i.e. a (2+1+1) REMPI, a (3+1) REMPI and ionization via the off-resonant 3p-state. The experimental data is supported by full quantum mechanical simulations of the excitation/ionization process. An analytical model to describe the (2+1+1) excitation channel and the selective excitation of multiple states is presented in addition.