We present the experimental realization of spectrally tunable, ultrashort, quasi-
monochromatic extreme ultraviolet (XUV) pulses generated at 100 kHz repetition rate in a
user-oriented gas high harmonic generation beamline of the Extreme Light Infrastructure—
Attosecond Light Pulse Source facility. Versatile spectral and temporal shaping of the XUV
pulses is accomplished with a double-grating, time-delay compensated monochromator
accommodating the two composing stages in a novel, asymmetrical geometry. This …