Laser intensity dependence of ion momentum distribution in strong-field double ionization

Abstract

We provide the first uniform explanation basis for the laser intensity dependence of the momentum distributions that have been reported in atomic nonsequential double-ionization experiments. Our theoretical work covers laser irradiation at $780\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and intensities in the range $I=(1\ensuremath{-}6.5)\ifmmode\times\else\texttimes\fi{}{10}^{14}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$, which are relevant to experiments. We use a completely classical method introduced previously [Phay J. Ho, R. Panfili, S. L. Haan, and J. H. Eberly, Phys. Rev. Lett. 94, 093002 (2005)]. Our calculated results suggest that just two distinct categories of electron trajectories are relevant.