title: Electron vortices in photoionization by circularly polarized attosecond pulses.
abstract: Single ionization of He by two oppositely circularly polarized, time-delayed attosecond pulses is shown to produce photoelectron momentum distributions in the polarization plane having helical vortex structures sensitive to the time delay between the pulses, their relative phase, and their handedness. Results are obtained by both ab initio numerical solution of the two-electron time-dependent Schrödinger equation and by a lowest-order perturbation theory analysis. The energy, bandwidth, and temporal duration of attosecond pulses are ideal for observing these vortex patterns.
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: Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, 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, 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: Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299, USA.
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Starace