title: Two-colour pump-probe experiments with a twin-pulse-seed extreme ultraviolet free-electron laser.
abstract: Exploring the dynamics of matter driven to extreme non-equilibrium states by an intense ultrashort X-ray pulse is becoming reality, thanks to the advent of free-electron laser technology that allows development of different schemes for probing the response at variable time delay with a second pulse. Here we report the generation of two-colour extreme ultraviolet pulses of controlled wavelengths, intensity and timing by seeding of high-gain harmonic generation free-electron laser with multiple independent laser pulses. The potential of this new scheme is demonstrated by the time evolution of a titanium-grating diffraction pattern, tuning the two coherent pulses to the titanium M-resonance and varying their intensities. This reveals that an intense pulse induces abrupt pattern changes on a time scale shorter than hydrodynamic expansion and ablation. This result exemplifies the essential capabilities of the jitter-free multiple-colour free-electron laser pulse sequences to study evolving states of matter with element sensitivity.
authors.affiliation: Elettra-Sincrotrone Trieste, Strada Statale 14-km 163.5, 34149 Basovizza, Trieste, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Allaria
authors.forename: F
authors.initials: F
authors.lastname: Bencivenga
authors.forename: R
authors.initials: R
authors.lastname: Borghes
authors.forename: F
authors.initials: F
authors.lastname: Capotondi
authors.forename: D
authors.initials: D
authors.lastname: Castronovo
authors.forename: P
authors.initials: P
authors.lastname: Charalambous
authors.forename: P
authors.initials: P
authors.lastname: Cinquegrana
authors.forename: M B
authors.initials: MB
authors.lastname: Danailov
authors.forename: G
authors.initials: G
authors.lastname: De Ninno
authors.forename: A
authors.initials: A
authors.lastname: Demidovich
authors.forename: S
authors.initials: S
authors.lastname: Di Mitri
authors.forename: B
authors.initials: B
authors.lastname: Diviacco
authors.forename: D
authors.initials: D
authors.lastname: Fausti
authors.forename: W M
authors.initials: WM
authors.lastname: Fawley
authors.forename: E
authors.initials: E
authors.lastname: Ferrari
authors.forename: L
authors.initials: L
authors.lastname: Froehlich
authors.forename: D
authors.initials: D
authors.lastname: Gauthier
authors.forename: A
authors.initials: A
authors.lastname: Gessini
authors.forename: L
authors.initials: L
authors.lastname: Giannessi
authors.forename: R
authors.initials: R
authors.lastname: Ivanov
authors.forename: M
authors.initials: M
authors.lastname: Kiskinova
authors.forename: G
authors.initials: G
authors.lastname: Kurdi
authors.forename: B
authors.initials: B
authors.lastname: Mahieu
authors.forename: N
authors.initials: N
authors.lastname: Mahne
authors.forename: I
authors.initials: I
authors.lastname: Nikolov
authors.forename: C
authors.initials: C
authors.lastname: Masciovecchio
authors.forename: E
authors.initials: E
authors.lastname: Pedersoli
authors.forename: G
authors.initials: G
authors.lastname: Penco
authors.forename: L
authors.initials: L
authors.lastname: Raimondi
authors.forename: C
authors.initials: C
authors.lastname: Serpico
authors.forename: P
authors.initials: P
authors.lastname: Sigalotti
authors.forename: S
authors.initials: S
authors.lastname: Spampinati
authors.forename: C
authors.initials: C
authors.lastname: Spezzani
authors.forename: C
authors.initials: C
authors.lastname: Svetina
authors.forename: M
authors.initials: M
authors.lastname: Trovò
authors.forename: M
authors.initials: M
authors.lastname: Zangrando
references.citation: Phys Rev A. 1991 Oct 15;44(8):5178-5193
references.pmid: 9906572
references.citation: Phys Rev Lett. 2000 Mar 27;84(13):2861-4
references.pmid: 11018961
references.citation: Phys Rev Lett. 2013 Mar 29;110(13):134801
references.pmid: 23581326
references.citation: J Synchrotron Radiat. 2011 May;18(Pt 3):481-91
references.pmid: 21525658
references.citation: Phys Rev Lett. 2013 Feb 8;110(6):064801
references.pmid: 23432255
references.citation: Science. 2000 Aug 11;289(5481):932-5
references.pmid: 10937992
references.citation: Phys Rev Lett. 2013 Jun 7;110(23):234801
references.pmid: 25167501
references.citation: Phys Rev Lett. 2010 Feb 12;104(6):064801
references.pmid: 20366823
references.citation: Nat Commun. 2012;3:999
references.pmid: 22893123
references.citation: Phys Rev Lett. 2011 Nov 18;107(21):218102
references.pmid: 22181929
references.citation: Phys Rev Lett. 2007 Aug 31;99(9):098103
references.pmid: 17931040
references.citation: Phys Rev Lett. 2009 Dec 31;103(26):264801
references.pmid: 20366318
references.citation: Science. 2008 Oct 3;322(5898):69-71
references.pmid: 18832640
references.citation: Rev Sci Instrum. 2011 Apr;82(4):043711
references.pmid: 21529017
references.citation: Nature. 2007 Aug 9;448(7154):676-9
references.pmid: 17687320
references.citation: Rev Sci Instrum. 2009 Nov;80(11):113110
references.pmid: 19947720
references.citation: J Opt Soc Am. 1948 Sep;38(9):766-74
references.pmid: 18883922
references.citation: Nature. 2012 Jan 25;482(7383):59-62
references.pmid: 22278059