title: Controlling Nonsequential Double Ionization in Two-Color Circularly Polarized Femtosecond Laser Fields.
abstract: Atoms undergoing strong-field ionization in two-color circularly polarized femtosecond laser fields exhibit unique two-dimensional photoelectron trajectories and can emit bright circularly polarized extreme ultraviolet and soft-x-ray beams. In this Letter, we present the first experimental observation of nonsequential double ionization in these tailored laser fields. Moreover, we can enhance or suppress nonsequential double ionization by changing the intensity ratio and helicity of the two driving laser fields to maximize or minimize high-energy electron-ion rescattering. Our experimental results are explained through classical simulations, which also provide insight into how to optimize the generation of circularly polarized high harmonic beams.
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Mancuso
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Dorney
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Hickstein
authors.affiliation: Department of Physics and Astronomy, University of Northern Colorado, Greeley, Colorado 80639, USA.
authors.forename: Jan L
authors.initials: JL
authors.lastname: Chaloupka
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Ellis
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Franklin J
authors.initials: FJ
authors.lastname: Dollar
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Ronny
authors.initials: R
authors.lastname: Knut
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Patrik
authors.initials: P
authors.lastname: Grychtol
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Dmitriy
authors.initials: D
authors.lastname: Zusin
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Gentry
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Maithreyi
authors.initials: M
authors.lastname: Gopalakrishnan
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Henry C
authors.initials: HC
authors.lastname: Kapteyn
authors.affiliation: JILA, Department of Physics, University of Colorado and NIST, Boulder, Colorado 80309, USA.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Murnane