Thin-disk multipass amplifier for kilowatt-class ultrafast lasers above 100 mJ

We present a linear multipass amplifier based on the thin-disk technology which allows power scaling of continuous-wave, pulsed, and ultrashort-pulsed lasers without change of beam characteristics. The flexibility of the seed laser, such as choice of repetition rate, pulse duration, and bursts is maintained. Due to a large beam radius on the thin disk of several millimeters, peak intensities are lower and nonlinear effects play a smaller role compared to the competing technologies of fiber and slab amplifiers. The multipass amplifier consists of a glass-welded mirror array and a thin-disk laser head. An Ytterbium-doped thin disk with a thickness on the order of few 100 μm acts as the active medium. The mirror array is used to implement up to 36 reflections at the disk.