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A: Fachverband Atomphysik
A 5: Interaction with intense laser pulses I: Atoms
A 5.3: Talk
Tuesday, March 11, 2008, 11:45–12:00, 3C
Experiments on non-sequential double ionization of Ne and Ar using a femtosecond laser oscillator — •yunquan liu1, sebastian tschuch1, martin dürr1, artem rudenko1, robert moshammer1, joachim ullrich1, martin siegel2, and uwe morgner2 — 1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany — 2University of Hannover, Welfengarten 1, D-30167 Hannover, Germany
We report on first proof-of-principles results on non-sequential double ionization of argon and neon achieved by using a newly developed long-cavity Ti:sapphire femtosecond oscillator with a pulse duration of 45 fs and a repetition of 6.2 MHz combined with a dedicated reaction microscope. Under optimized experimental conditions, peak intensities larger than 2.3×1014 W.cm−2 have been achieved. Ion momentum distributions were recorded for both rare gases and show significantly different features for single as well as for double ionization. For single ionization of neon a spike of zero-momentum electrons is found when decreasing the laser intensity towards the lowest ionization rate we can measure which is attributed to a non-resonant ionization channel. As to double ionization, the longitudinal momentum distribution for Ne2+ displays a clear double-hump structure whereas this feature is found to be smoothened out with a maximum at zero momentum for Ar2+.