TITLE:
Triggering recollisions with XUV pulses: Imprint of recolliding
periodic orbits

AUTHORS:
J. Dubois^(1), A. Jorba^(2)
(1) Max Planck Institute for the Physics of Complex Systems
    Nothnitzer Strasse 38, 01187 Dresden, Germany
(2) Departament de Matematiques i Informatica
    Universitat de Barcelona, Gran Via 585, 08007 Barcelona, Spain

ABSTRACT:
We consider an electron in an atom driven by an infrared (IR)
elliptically polarized laser field after its ionization by an
ultrashort extreme ultraviolet (XUV) pulse. We find that, regardless
of the atom species and the laser ellipticity, there exists XUV
parameters for which the electron returns to its parent ion after
ionizing, i.e., undergoes a recollision. This shows that XUV pulses
trigger efficiently recollisions in atoms regardless of the
ellipticity of the IR field. The XUV parameters for which the electron
undergoes a recollision are obtained by studying the location of
recolliding periodic orbits (RPOs) in phase space. The RPOs and their
linear stability are followed and analyzed as a function of the
intensity and ellipticity of the IR field. We determine the relation
between the RPOs identified here and the ones found in the literature
and used to interpret other types of highly nonlinear phenomena for
low elliptically and circularly polarized IR fields.