title: Determining the polarization state of an extreme ultraviolet free-electron laser beam using atomic circular dichroism.
abstract: Ultrafast extreme ultraviolet and X-ray free-electron lasers are set to revolutionize many domains such as bio-photonics and materials science, in a manner similar to optical lasers over the past two decades. Although their number will grow steadily over the coming decade, their complete characterization remains an elusive goal. This represents a significant barrier to their wider adoption and hence to the full realization of their potential in modern photon sciences. Although a great deal of progress has been made on temporal characterization and wavefront measurements at ultrahigh extreme ultraviolet and X-ray intensities, only few, if any progress on accurately measuring other key parameters such as the state of polarization has emerged. Here we show that by combining ultra-short extreme ultraviolet free electron laser pulses from FERMI with near-infrared laser pulses, we can accurately measure the polarization state of a free electron laser beam in an elegant, non-invasive and straightforward manner using circular dichroism.
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Mazza
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: M
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authors.lastname: Ilchen
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: A J
authors.initials: AJ
authors.lastname: Rafipoor
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: C
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authors.lastname: Callegari
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: P
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authors.lastname: Finetti
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: O
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authors.lastname: Plekan
authors.affiliation: 1] Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy [2] Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Area Science Park, Trieste I-34149, Italy [3] eChemistry Laboratory, Faculty of Life and Social Sciences, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
authors.forename: K C
authors.initials: KC
authors.lastname: Prince
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Richter
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: M B
authors.initials: MB
authors.lastname: Danailov
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Demidovich
authors.affiliation: 1] Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy [2] Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica 5001, Slovenia.
authors.forename: G
authors.initials: G
authors.lastname: De Ninno
authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Grazioli
authors.affiliation: 1] Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy [2] Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica 5001, Slovenia.
authors.forename: R
authors.initials: R
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authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: N
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authors.affiliation: Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Raimondi
authors.affiliation: 1] Elettra-Sincrotrone Trieste, Basovizza I-34149, Italy [2] University of Trieste, Graduate School of Nanotechnology, Piazzale Europa 1, Trieste 34127, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Svetina
authors.affiliation: CNR Istituto di Metodologie Inorganiche e dei Plasmi, CP10, Monterotondo Scalo I-00016, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Avaldi
authors.affiliation: CNR Istituto di Metodologie Inorganiche e dei Plasmi, CP10, Monterotondo Scalo I-00016, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Bolognesi
authors.affiliation: CNR Istituto di Metodologie Inorganiche e dei Plasmi, CP10, Monterotondo Scalo I-00016, Italy.
authors.forename: M
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authors.lastname: Coreno
authors.affiliation: CNR Istituto di Metodologie Inorganiche e dei Plasmi, CP10, Monterotondo Scalo I-00016, Italy.
authors.forename: P
authors.initials: P
authors.lastname: O'Keeffe
authors.affiliation: Department of Physics, University of Trieste, Trieste I-34128, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Di Fraia
authors.affiliation: CIMAINA and Dipartimento di Fisica, Università di Milano, via Celoria 16, Milano I-20133, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Devetta
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, D-10623 Berlin, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Ovcharenko
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, D-10623 Berlin, Germany.
authors.forename: Th
authors.initials: T
authors.lastname: Möller
authors.affiliation: Physikalisches Institut, Universität Freiburg, D-79104 Freiburg, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Lyamayev
authors.affiliation: Physikalisches Institut, Universität Freiburg, D-79104 Freiburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Stienkemeier
authors.affiliation: Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22607 Hamburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Düsterer
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ueda
authors.affiliation: National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: J T
authors.initials: JT
authors.lastname: Costello
authors.affiliation: 1] Departamento de Fisica de Materiales, UPV/EHU, San Sebastian/Donostia E-20018, Spain [2] IKERBASQUE, Basque Foundation for Science, Bilbao E-48011, Spain [3] Donostia International Physics Center (DIPC), San Sebastian/Donostia E-20018, Spain.
authors.forename: A K
authors.initials: AK
authors.lastname: Kazansky
authors.affiliation: 1] European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany [2] Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan [3] Donostia International Physics Center (DIPC), San Sebastian/Donostia E-20018, Spain [4] Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia.
authors.forename: N M
authors.initials: NM
authors.lastname: Kabachnik
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Meyer