Nonlinear Dynamics of Recollisions in the Double Ionization Processes of Atoms in Strong Fields

Abstract

Double ionization processes triggered by intense linearly polarized laser fields have revealed the paramount role of electron-electron collisions. It has been shown [1] that the correlated dynamics of such electronic collisions can be modeled by a two dimensional symplectic map which captures the bare essentials of the energy exchange processes occurring during a recollision between the two electrons. We investigate linear and nonlinear properties of this map and connect them to the dynamical organization of phase space and related statistical data.• If the inner electron is sufficiently far away from the nucleus (in a region referred as the unbound area), the laser excitation imposes the dynamics and the electron ionizes quickly. • If the inner electron is sufficiently close to the nucleus (in a region referred as the bound area), it is trapped on an invariant torus and has no chance to ionize by itself.

Elliptical Polarization and Probability of Double Ionization

“…Elliptical polarization has also recently been predicted to have unexpected non-zero effects in SDI [6], in agreement with experiment [7]. Evidently, polarization dependence has the potential for providing new insights into the complex character of two-electron correlation in double ionization [8,9].…”

“…We believe that they expose interesting unexplored territory within the NSDI domain by showing that new effects appear that depend on ellipticity. Prior to this, in the domain of extensive experimental activity, mostly confined to near-infrared wavelengths close to 800 nm, few theoretical studies of elliptically or circularly polarized pulses have been made (see [8][9][10][11]).…”

Elliptical trajectories in nonsequential double ionization

“…Compared to SDI, which can be well explained by the ADK tunneling theory [3] based on a single active electron approximation, NSDI is a much more complicated (and thus interesting) phenomenon of atomic physics. Recently, open questions in this domain associated with departures from the usual linear polarization of the laser pulses have received close theoretical attention [4,5,6].…”