title: Spectral phase measurement of a Fano resonance using tunable attosecond pulses.
abstract: Electron dynamics induced by resonant absorption of light is of fundamental importance in nature and has been the subject of countless studies in many scientific areas. Above the ionization threshold of atomic or molecular systems, the presence of discrete states leads to autoionization, which is an interference between two quantum paths: direct ionization and excitation of the discrete state coupled to the continuum. Traditionally studied with synchrotron radiation, the probability for autoionization exhibits a universal Fano intensity profile as a function of excitation energy. However, without additional phase information, the full temporal dynamics cannot be recovered. Here we use tunable attosecond pulses combined with weak infrared radiation in an interferometric setup to measure not only the intensity but also the phase variation of the photoionization amplitude across an autoionization resonance in argon. The phase variation can be used as a fingerprint of the interactions between the discrete state and the ionization continua, indicating a new route towards monitoring electron correlations in time.
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Kotur
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Guénot
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Á
authors.initials: Á
authors.lastname: Jiménez-Galán
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Kroon
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: E W
authors.initials: EW
authors.lastname: Larsen
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Louisy
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Bengtsson
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: M
authors.identifier: http://orcid.org/0000-0003-0507-1564
authors.initials: M
authors.lastname: Miranda
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Mauritsson
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: C L
authors.initials: CL
authors.lastname: Arnold
authors.affiliation: Department of Synchrotron Radiation Instrumentation, Max IV Laboratory, Lund University, PO Box 118, SE-221 00 Lund, Sweden.
authors.forename: S E
authors.initials: SE
authors.lastname: Canton
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Gisselbrecht
authors.affiliation: Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Carette
authors.affiliation: Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: J M
authors.initials: JM
authors.lastname: Dahlström
authors.affiliation: Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Lindroth
authors.affiliation: Laboratoire de Chimie Physique-Matière et Rayonnement, Université Pierre et Marie Curie, 11, Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-2998-0861
authors.initials: A
authors.lastname: Maquet
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: L
authors.identifier: http://orcid.org/0000-0003-1093-4379
authors.initials: L
authors.lastname: Argenti
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.|Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain.|Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Martín
authors.affiliation: Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: L'Huillier