Dynamics Of Electrons Involve From Double Ionization Of Xenon Atoms Driven By The Few-Cycle Laser Pulses

Using the classical ensemble model, the dynamics of correlated electrons involve in the nonsequential double ionization (NSDI) of Xe atoms has investigated by few-cycle laser pulses. The content of this thesis mainly contain two parts, one is the two-electrons dynamics in linearly polarized (LP) laser pulses interactions with xenon atoms and the other is the electron correlated dynamics from NSDI of xenon atoms driven by the elliptically polarized (EP) laser pulses.With a classical ensemble model, we have investigated the nonsequential double ionization (NSDI) of Xe by linearly polarized (LP) and elliptically polarized (EP) ultra-short laser pulses respectively.Our results show that,In the case of parallel orientation(the direction of parallel to the laser field along the long axis),the momentum distributions of correlated electron in the direction of parallel to the laser field (for LP) and along the long axis of the laser polarization plane (for EP) show significant difference.On the contrary, along perpendicular to the laser field (for LP) and the short axis of the laser polarization plane (for EP), the momentum distributions present similar correlated images(often emit into the opposite hemisphere). By back analysis the classical trajectories of NSDI, The causes of the above phenomenon come from the different recollision mechanism. For LP, the recollision often occurs at the first returning of tunneled electron, but for EP, all of the successful NSDI come from the "exit collision" which is responsible for the momentum distribution of correlated electron.We investigated the nonsequential double ionization (NSDI) of Xe by linearly polarized(LP) and elliptically polarized (EP) laser pulses using the classical ensemble model. For the two cases, the ensemble from NSDI was separated into two kinds of subensemble according to the relative momentum along the y-axis(k12⊥), respectively. The results show only for the case of relatively small K12⊥, the momentum distribution along the x-axis can show a V-like shape obviously, which is according with the experiment. What is important is that we firstly examine the role of the repulsion interaction between two electrons for the two kinds of subensemble, and find that the process of NSDI for the case of relatively small k12⊥ exits a strong repulsion interaction which contributes significantly to the V-like shape. However, for the case of relatively big k12⊥, the repulsion interaction between two electrons is relatively weak, and both the nuclear Coulomb attraction and electric field force dominate the process of NSDI.We have investigated the influence of the correlated electron dynamics with the different laser pulse width.The numerical results show that, the momentum distributions of correlated electron along the x-axis exhibits correlated behavior for the 3-T(T is the laser cycle) laser pulse and the 6-T laser pulse. But the former presents a surprising arc-like structure, the latter presents a V-like structure.By analyzing all of the classical trajectories of NSDI, the responsible for the arc-like only comes from the first return of the single ionization electron collision.But the V-like structures not only comes from the first return but also the latter returns make a great contribute to the NSDI events.