High-energy (>200 mJ), 1 kHz picosecond laser based on a directly liquid-cooled Yb:YAG thin-disk regenerative amplifier

We present the performance of a ring regenerative amplifier based on a directly liquid-cooled Yb:YAG thin-disk laser head. An output pulse energy exceeding 250 mJ at 1 kHz is achieved, with a beam quality factor of M² < 1.3. After compression using a reflective diffraction grating pair, a pulse duration of 1.3 ps is obtained, maintaining an energy above 200 mJ and exhibiting a power stability of 0.55% RMS. This work represents the first, to the best of our knowledge, experimental demonstration of high-average-power laser amplification using a directly liquid-cooled Yb:YAG thin-disk laser head, highlighting its great potential for high-energy, high-average-power ultrafast laser systems.