Stuttgart 2012 – scientific programme

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A: Fachverband Atomphysik

A 1: Interaction with strong or short laser pulses I

A 1.5: Talk

Monday, March 12, 2012, 11:45–12:00, V55.01

The lateral momentum distribution after strong-field ionization — •Ingo Dreißigacker¹, Jost Henkel^1,2, and Manfred Lein¹ — ¹Institut für Theoretische Physik and Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany — ²Institut für Physikalische und Theoretische Chemie and Röntgen Research Center for Complex Material Systems, Am Hubland, 97074 Würzburg, Germany

Motivated by recent measurements of the lateral electron momentum distribution from ionization with circularly polarized laser pulses [1], we model these distributions using both numerical and analytical methods. We demonstrate that in contrast to the momentum distribution in field direction, the width of the lateral distribution follows the instantaneous electric field on an attosecond timescale. This applies even in case of large fields, where substantial depletion occurs. We review the derivation of the tunneling formula, which predicts lateral distributions of approximately Gaussian shape. We demonstrate that the pre-exponential factor in the saddle-point approximation cannot be neglected if quantitative results are desired. We calculate the widths for hydrogen as well as for argon and neon atoms. We compare to results from the time-dependent Schrödinger equation and to the experimental results from [1]. We find significant improvement of our approach over the previously used tunneling formula.

[1] Arissian et al., PRL 105, 133002 (2010)