title: Anomalous Fano Profiles in External Fields.
abstract: We show that the external control of Fano resonances in general leads to complex Fano q parameters. Fano line shapes of photoelectron and transient absorption spectra in the presence of an infrared control field are investigated. Computed transient absorption spectra are compared with a model proposed for a recent experiment [C. Ott et al., Science 340, 716 (2013)]. Control mechanisms for photoelectron spectra are exposed: control pulses applied during excitation modify the line shapes by momentum boosts of the continuum electrons. Pulses arriving after excitation generate interference fringes due to infrared two-photon transitions.
authors.affiliation: Physics Department, Ludwig Maximilians Universität, D-80333 Munich, Germany.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Zielinski
authors.affiliation: Physics Department, Ludwig Maximilians Universität, D-80333 Munich, Germany.
authors.forename: Vinay Pramod
authors.initials: VP
authors.lastname: Majety
authors.affiliation: Institute for Theoretical Physics, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Nagele
authors.affiliation: Institute for Theoretical Physics, Vienna University of Technology, 1040 Vienna, Austria.|Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
authors.forename: Renate
authors.initials: R
authors.lastname: Pazourek
authors.affiliation: Institute for Theoretical Physics, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: Joachim
authors.initials: J
authors.lastname: Burgdörfer
authors.affiliation: Physics Department, Ludwig Maximilians Universität, D-80333 Munich, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Scrinzi