title: HELIOS--A laboratory based on high-order harmonic generation of extreme ultraviolet photons for time-resolved spectroscopy.
abstract: In this paper, we present the HELIOS (High Energy Laser Induced Overtone Source) laboratory, an in-house high-order harmonic generation facility which generates extreme ultraviolet (XUV) photon pulses in the range of 15-70 eV with monochromatized XUV pulse lengths below 35 fs. HELIOS is a source for time-resolved pump-probe/two-color spectroscopy in the sub-50 fs range, which can be operated at 5 kHz or 10 kHz. An optical parametric amplifier is available for pump-probe experiments with wavelengths ranging from 240 nm to 20,000 nm. The produced XUV radiation is monochromatized by a grating in the so-called off-plane mount. Together with overall design parameters, first monochromatized spectra are shown with an intensity of 2 ⋅ 10(10) photons/s (at 5 kHz) in the 29th harmonic, after the monochromator. The XUV pulse duration is measured to be <25 fs after monochromatization.
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Plogmaker
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: J A
authors.initials: JA
authors.lastname: Terschlüsen
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Krebs
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Svanqvist
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Forsberg
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: U B
authors.initials: UB
authors.lastname: Cappel
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: J-E
authors.initials: JE
authors.lastname: Rubensson
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Siegbahn
authors.affiliation: Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Söderström