Below threshold nonsequential double ionization with linearly polarized two-color fields I: symmetry and dominance

Abstract

We investigate laser-induced nonsequential double ionization with linearly polarized bichromatic fields, focusing on the recollision-excitation with subsequent ionization (RESI) mechanism. Using the strong-field approximation, we assess how the symmetries of the field influence the dominant events. Furthermore, we show that, by manipulating the field parameters such as the field frequencies and relative phase between the two driving waves, one can influence the correlated electron-momentum distributions. Specific features of a linearly polarized bichromatic field are that the momentum distributions of the second electron are no longer centered around vanishing momenta and that there may be more than one ionization event per half cycle. This can be used to confine the RESI distributions to specific momentum regions and to determine a hierarchy of parameters that make an event dominant.

26 pages (including appendices and references) and 12 figures; this version has been accepted for publication in Phys Rev A. The revised version has slight modifications in structure, with some results moved to an appendix