Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 11: Interaction with VUV and X-ray light I

A 11.2: Hauptvortrag

Montag, 12. März 2012, 17:00–17:30, V47.03

Rydberg atoms in strong laser fields — •Ulli Eichmann — Max-Born-Institute, D-12489 Berlin, Germany

The widely accepted and very successful concept of tunneling ionization of atoms in strong laser fields fails to describe the ionization of Rydberg atoms in these fields. This is despite the fact that the Keldysh-parameter, typically used to separate the tunneling from the multiphoton scenario, suggests just tunneling. Instead, one might be tempted to assume that the loosely bound Rydberg electron, which temporarily gains kinetic energy exceeding its binding energy by several orders of magnitude is easily removed from the atom. On the other hand, if one considers the loosely bound Rydberg electron as a free electron, absorption of photons is not possible.

We will present results on the ionization dynamics of Rydberg atoms in strong laser fields with intensities up to 5 10¹⁵W/cm². We are able to prepare Rydberg atoms in a wide range of principal quantum numbers and more importantly, also in a wide range of angular momentum states. In the experiments we find a large percentage of Rydberg atoms surviving the very strong laser field. Moreover, direct position sensitive measurement of neutral atoms allows for the observation of deflection of surviving Rydberg atoms indicating unambiguously their interaction with the strong focused laser field. We will discuss the underlying physical mechanisms, particularly in the context of strong field stabilization of atoms.