Abstract: The present invention generally relates to coherent, ultra-short ultraviolet (UV) or extended ultraviolet (XUV) pulse generation, and more particularly, to a highly bright re-focusable source capable of producing, at an adjustable rate comprised between 50 kHz and a few megahertz, femtosecond long pulses, in the ultraviolet or extended ultraviolet range. It comprises: —a fiber laser device adapted to produce laser beam comprising pulses, —an harmonic generator device comprising an interaction medium. The harmonic generator device and the fiber laser device are coupled so that the laser beam hits the interaction medium with a power of at least 10 13 W/cm2, so as to generate said UV-XUV pulses.