title: Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering.
abstract: The advent of free-electron laser (FEL) sources delivering two synchronized pulses of different wavelengths (or colours) has made available a whole range of novel pump-probe experiments. This communication describes a major step forward using a new configuration of the FERMI FEL-seeded source to deliver two pulses with different wavelengths, each tunable independently over a broad spectral range with adjustable time delay. The FEL scheme makes use of two seed laser beams of different wavelengths and of a split radiator section to generate two extreme ultraviolet pulses from distinct portions of the same electron bunch. The tunability range of this new two-colour source meets the requirements of double-resonant FEL pump/FEL probe time-resolved studies. We demonstrate its performance in a proof-of-principle magnetic scattering experiment in Fe-Ni compounds, by tuning the FEL wavelengths to the Fe and Ni 3p resonances.
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.|Dipartimento di Fisica, Università degli Studi di Trieste, 34127 Trieste, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Ferrari
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.|Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, Bât. 510, 91405 Orsay, France.
authors.forename: Carlo
authors.initials: C
authors.lastname: Spezzani
authors.affiliation: Centre de Sciences Nucléaires et de Sciences de la Matière, Université Paris-Sud, CNRS UMR 8609, Bât. 104-108, 91405 Orsay, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Fortuna
authors.affiliation: Laboratoire de Chimie Physique Matière et Rayonnement, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7614, 75005 Paris, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Delaunay
authors.affiliation: Institut des NanoSciences de Paris, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7588, 75005 Paris, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Vidal
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Ivaylo
authors.initials: I
authors.lastname: Nikolov
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cinquegrana
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Diviacco
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: David
authors.initials: D
authors.lastname: Gauthier
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Penco
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Primož Rebernik
authors.initials: PR
authors.lastname: Ribič
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Eleonore
authors.initials: E
authors.lastname: Roussel
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Trovò
authors.affiliation: Service de Physique de l'Etat Condensé, DSM/IRAMIS/SPEC, CNRS UMR 3680, CEA Saclay, 91191 Gif-sur-Yvette, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Moussy
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Milano, 20133 Milano, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Pincelli
authors.affiliation: Institut des NanoSciences de Paris, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7588, 75005 Paris, France.|Ecole Normale Supérieure, PSL Research University, 75231 Paris, France.
authors.forename: Lounès
authors.initials: L
authors.lastname: Lounis
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Manfredda
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Pedersoli
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Capotondi
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.|Graduate School of Nanotechnology, Università degli Studi di Trieste, 34127 Trieste, Italy.
authors.forename: Cristian
authors.initials: C
authors.lastname: Svetina
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Mahne
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.|Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, 34149 Trieste, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zangrando
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Raimondi
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Alexander
authors.initials: A
authors.lastname: Demidovich
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.|ENEA, Centro Ricerche Frascati, Via E. Fermi 45, 00044 Frascati, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Giannessi
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.|Laboratory of Quantum Optics, University of Nova Gorica, 5001 Nova Gorica, Slovenia.
authors.forename: Giovanni
authors.initials: G
authors.lastname: De Ninno
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Miltcho Boyanov
authors.initials: MB
authors.lastname: Danailov
authors.affiliation: ELETTRA-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Allaria
authors.affiliation: Institut des NanoSciences de Paris, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7588, 75005 Paris, France.|Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, B.P. 48, 91192 Gif-sur-Yvette, France.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Sacchi