Time-preserving grating monochromator for extreme-ultraviolet ultrashort pulses

It is here presented the design and realization of a grazing-incidence grating monochromator for the spectral selection of ultrashort pulses in the extreme-ultraviolet, which preserves the duration of the pulse in the time scale of tens of femtoseconds. The monochromator uses a single grating in the off-plane mount. Such a type of monochromator has been realized for the spectral selection of high-order harmonic laser pulses from multiple harmonic orders. The pulse duration of the monochromatized harmonic pulses has been measured to be in the range 30 to 50 fs. The harmonic photon energy is tunable between 12 and 120 eV. The instrument is used in the monochromatized branch of the Artemis beamline at the Central Laser Facility (UK) for applications in ultrafast electron spectroscopy. The fully characterization of the monochromator is presented.