Streaking analysis of strong-field ionisation

Abstract

Motivated by recent experimental progress in precision investigation of strong-field ionisation by angular streaking 1, we employ streaking by a linearly polarised half-cycle pulse as a theoretical tool to analyse the strong-field ionisation of atoms. For moderate field strengths, the electron momentum distribution is consistent with the interpretation that ionisation occurs most probably at the peak of the field followed by classical electron motion under the combined force of the laser field and the atomic potential. At high field strengths, the momentum distributions together with the classical model indicate that ionisation occurs preferentially before the peak of the field. Surprisingly, the momentum at the peak of the distribution scales almost linearly with the intensity of the half-cycle pulse.

Keywords:

• strong-field ionisation
• streaking
• Coulomb correction
• Stark shift

Acknowledgements

The author thanks his group members, in particular J. Henkel, E. van der Zwan and I. Dreißigacker, for the critical reading of the manuscript. Discussions with Lars B. Madsen have been very useful. The funding of the Centre for Quantum Engineering and Space-Time Research (QUEST) by the Deutsche Forschungsgemeinschaft is gratefully acknowledged.