title: Nonlinear Dichroism in Back-to-Back Double Ionization of He by an Intense Elliptically Polarized Few-Cycle Extreme Ultraviolet Pulse.
abstract: Control of double ionization of He by means of the polarization and carrier-envelope phase (CEP) of an intense, few-cycle extreme ultraviolet (XUV) pulse is demonstrated numerically by solving the six-dimensional two-electron, time-dependent Schrödinger equation for He interacting with an elliptically polarized XUV pulse. Guided by perturbation theory (PT), we predict the existence of a nonlinear dichroic effect (∝I^{3/2}) that is sensitive to the CEP, ellipticity, peak intensity I, and temporal duration of the pulse. This dichroic effect (i.e., the difference of the two-electron angular distributions for opposite helicities of the ionizing XUV pulse) originates from interference of first- and second-order PT amplitudes, allowing one to probe and control S- and D-wave channels of the two-electron continuum. We show that the back-to-back in-plane geometry with unequal energy sharing is an ideal one for observing this dichroic effect that occurs only for an elliptically polarized, few-cycle attosecond pulse.
authors.affiliation: Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Ngoko Djiokap
authors.affiliation: Department of Physics, Voronezh State University, Voronezh 394006, Russia.
authors.forename: N L
authors.initials: NL
authors.lastname: Manakov
authors.affiliation: Department of Physics, Voronezh State University, Voronezh 394006, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Meremianin
authors.affiliation: Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA.
authors.forename: S X
authors.initials: SX
authors.lastname: Hu
authors.affiliation: Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: L B
authors.initials: LB
authors.lastname: Madsen
authors.affiliation: Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299, USA.
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Starace