title: CITIUS: an infrared-extreme ultraviolet light source for fundamental and applied ultrafast science.
abstract: We present the main features of CITIUS, a new light source for ultrafast science, generating tunable, intense, femtosecond pulses in the spectral range from infrared to extreme ultraviolet (XUV). The XUV pulses (about 10(5)-10(8) photons/pulse in the range 14-80 eV) are produced by laser-induced high-order harmonic generation in gas. This radiation is monochromatized by a time-preserving monochromator, also allowing one to work with high-resolution bandwidth selection. The tunable IR-UV pulses (10(12)-10(15) photons/pulse in the range 0.4-5.6 eV) are generated by an optical parametric amplifier, which is driven by a fraction of the same laser pulse that generates high order harmonics. The IR-UV and XUV pulses follow different optical paths and are eventually recombined on the sample for pump-probe experiments. We also present the results of two pump-probe experiments: with the first one, we fully characterized the temporal duration of harmonic pulses in the time-preserving configuration; with the second one, we demonstrated the possibility of using CITIUS for selective investigation of the ultra-fast dynamics of different elements in a magnetic compound.
authors.affiliation: Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia.
authors.forename: C
authors.initials: C
authors.lastname: Grazioli
authors.affiliation: Elettra Sincrotrone Trieste, Trieste, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Callegari
authors.affiliation: Sapienza University, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Ciavardini
authors.affiliation: Elettra Sincrotrone Trieste, Trieste, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Coreno
authors.affiliation: Institute of Photonics and Nanotechnologies (CNR-IFN), Padova, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Frassetto
authors.affiliation: Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia.
authors.forename: D
authors.initials: D
authors.lastname: Gauthier
authors.affiliation: Kontrolni Sistemi d.o.o., Sežana, Slovenia.
authors.forename: D
authors.initials: D
authors.lastname: Golob
authors.affiliation: Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia.
authors.forename: R
authors.initials: R
authors.lastname: Ivanov
authors.affiliation: Institute of Materials Manufacturing (CNR-IOM), TASC Laboratory, Trieste, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Kivimäki
authors.affiliation: Elettra Sincrotrone Trieste, Trieste, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Mahieu
authors.affiliation: Laboratory of Mechanical Processing Technologies, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: B
authors.initials: B
authors.lastname: Bučar
authors.affiliation: Laboratory of Mechanical Processing Technologies, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Merhar
authors.affiliation: Institute of Photonics and Nanotechnologies (CNR-IFN), Padova, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Miotti
authors.affiliation: Institute of Photonics and Nanotechnologies (CNR-IFN), Padova, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Poletto
authors.affiliation: Institute of Organic Synthesis and Photoreactivity (CNR-ISOF), Ferrara, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Polo
authors.affiliation: Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia.
authors.forename: B
authors.initials: B
authors.lastname: Ressel
authors.affiliation: Elettra Sincrotrone Trieste, Trieste, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Spezzani
authors.affiliation: Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia.
authors.forename: G
authors.initials: G
authors.lastname: De Ninno