Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 27: Poster: Attosecond physics

A 27.2: Poster

Wednesday, March 25, 2015, 17:00–19:00, C/Foyer

Classical analytical approach for Coulomb focusing of tunnelled electrons in intense laser fields. — •Jiří Daněk, Karen Z. Hatsagortsyan, and Christoph H. Keitel — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany

Recent high resolution experiments on the kinematically complete measurement of photoelectron spectra in the tunneling ionization in intense laser fields led to discovery of new low energy structures (LES), very low energy structures (VLES) and zero energy structures (ZES) in the spectra at energies of the order of electronvolts, lower than electronvolts and milielectronvolts, respectively. Although, investigations show that these structures are due to the role of the Coulomb field of the atomic core in the laser driven dynamics of the tunnelled electron, there is no clear unified picture for the dynamics.

In our poster, we present our classical analytic approach to this problem for a linearly polarized laser field, which allows us to determine the influence of the parent ion on the ionized electron due to Coulomb interaction. Restricting the Coulomb field effect to rescattering events of the freed electron with the atomic core, we derive analytical formulas for the longitudinal and transversal momentum changes for the electron due to the Coulomb field, with further aim to explain the final momentum distribution via the effect of multiple rescattering. We also discuss the possibility of trapping of the ionized electron in the Rydberg states and the role of the trapping on the final spectra.