Stuttgart 2012 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 44: Attosecond physics II
A 44.4: Vortrag
Freitag, 16. März 2012, 11:30–11:45, V57.05
Theory of attosecond transient absorption spectroscopy for overlapping pump and probe pulses — •Stefan Pabst1,2, Arina Sytcheva1, Adrian Wirth3, Eleftherios Goulielmakis3, and Robin Santra1,2 — 1Center for Free-Electron Laser Science, DESY, Hamburg, Germany — 2Department of Physics, University of Hamburg, Hamburg, Germany — 3Max-Planck-Institut für Quantenoptik, Garching, Germany
Attosecond transient absorption spectroscopy has been successfully applied to the measurement of the ion density matrix of strong-field ionized Krypton. In a recent experiment [A. Wirth et al., Science 334, 195 (2011)] it was shown that it is possible to probe the ionization dynamics of Krypton during an ionizing strong-field pulse that lasted approx. 2 fs. The theory of transient absorption has recently been developed [R. Santra et al., PRA 83, 033405 (2011)] for non-overlapping pump and probe pulses. In the case of overlapping pulses, the question remained whether one probes directly the instantaneous hole population or rather some effective population. Here, we present a theory of attosecond transient absorption spectroscopy for overlapping pump and probe pulses. Within the time-dependent configuration-interaction singles (TDCIS) approach, we describe the pump step (strong-field ionization) as well as the probe step (resonant electron excitation) on equal footing. Furthermore, we include propagation effects and detector resolution in our analysis. Our results support the concept that the transient absorption signal can be directly related to the instantaneous hole population even during the ionizing pump pulse.