Stuttgart 2012 – scientific programme
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A: Fachverband Atomphysik
A 12: Interaction with strong or short laser pulses III
A 12.2: Talk
Tuesday, March 13, 2012, 11:00–11:15, V47.03
Attosecond Two-Electron Dynamics in Non-Sequential Double Ionization of Argon using Ultra-short Laser Pulses — •Nicolas Camus1, Bettina Fischer1, Manuel Kremer1, Vandana Sharma1, Artem Rudenko1,2, Boris Bergues3, Mathias Kübel3, Nora G. Johnson3, Mathias F. Kling3, Thomas Pfeifer1, Joachim Ullrich1,2, and Robert Moshammer1 — 1Max-Planck-Institut für Kernphysik, Heidelberg — 2Max-Planck Advanced Study Group at CFEL, Hamburg — 3Max-Planck-Institut für Quantenoptik, Garching
We report on a kinematically complete experiment on non-sequential double ionization (NSDI) of argon using CEP characerized 6 fs laser pulses in combination with a reaction microscope. In NSDI the first ionized electron is driven back to the parent ion causing ionization of the second electron. In this study we choose a rather low intensity where the energy of the re-colliding electron is too small for impact ionization but large enough to excite the remaining Ar+ ion. Loosing almost all of its kinetic energy during re-collision, the re-colliding electron gets recaptured such that a doubly-excited state is formed. Within a classical simulation we demonstrate that this highly excited complex has lost memory of its creation. We consistently relate measured momentum differences between the two electrons to time differences and, thus, follow the ionization of the doubly excited state in the laser field on a sub-fs time scale. A striking agreement between experimental and simulated distributions is observed with a most likely time difference between the two electrons for leaving the atom of 200±100 as.