title: Limits of Strong Field Rescattering in the Relativistic Regime.
abstract: Recollision for a laser driven atomic system is investigated in the relativistic regime via a strong field quantum description and Monte Carlo semiclassical approach. We find the relativistic recollision energy cutoff is independent of the ponderomotive potential U_{p}, in contrast to the well-known 3.2U_{p} scaling. The relativistic recollision energy cutoff is determined by the ionization potential of the atomic system and achievable with non-negligible recollision flux before entering a "rescattering free" interaction. The ultimate energy cutoff is limited by the available intensities of short wavelength lasers and cannot exceed a few thousand Hartree, setting a boundary for recollision based attosecond physics.
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Klaiber
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: K Z
authors.initials: KZ
authors.lastname: Hatsagortsyan
authors.affiliation: State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China.
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Luo
authors.affiliation: Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: P
authors.initials: P
authors.lastname: Grugan
authors.affiliation: Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: B C
authors.initials: BC
authors.lastname: Walker