Abstract: A laser pulse spectral broadening apparatus (100) for spectral broadening of laser pulses (1A) comprises a multi-pass cell device (10) with multiple mirror elements, which are arranged for providing a beam path (2) extending from an input section to an output section of the multi-pass cell device (10), wherein the mirror elements comprise focussing mirror elements having a concave curvature, and with a pulse spectral broadening device (20) including at least one optical non-linear medium (21) being arranged in the beam path (2) for spectral broadening of the laser pulses passing the pulse spectral broadening device (20), wherein the mirror elements have a configuration providing multiple passages of the beam path (2) through the pulse spectral broadening device (20), wherein the mirror elements further comprise folding mirror elements having a close to plane shape, wherein the absolute value of the radius of curvature of the folding mirror elements (11, 12) is larger than 10 m, the folding mirror elements spa

Abstract: Acousto-optical modulator apparatus for acousto-optically deflecting laser beam includes gas-filled volume including working gas and having input and output sections, for receiving beam along incidence light path via input section and transmitting beam along deflection light path via output section, and ultra-sound transducer device for creating ultra-sound field intersecting incidence light path in interaction region within gas-filled volume and creating periodic density modulation of working gas in interaction region, ultra-sound transducer device deflecting beam in interaction region by Bragg-diffraction in ultra-sound field, so that deflection light path has direction deviating from direction of incidence light path, wherein gas-filled volume keeps working gas at working pressure below bar and input section and output section transmit beam with laser center wavelength included in wavelength range from mid-IR to XUV. Preferably, ultra-sound transducer device focuses ultra-sound field in interaction region.