Compact 56 mJ thin-disk regenerative amplifier with thermally-near-unstable resonator structure

We experimentally demonstrated a very compact Yb:YAG thin-disk regenerative amplifier with hundred millijoules output potential. The cavity was designed based on the thermal-near-unsteady resonator concept with a cavity length of only 2 m. Laser outputs of 205 W for continuous wave, 156 W (3.1 mJ) for pulsed waves at 50 kHz, and 56 W (56 mJ) for pulsed waves at 1 kHz were achieved. To the best of our knowledge, this is the shortest cavity length reported for a thin-disk regenerative amplifier with a thermally-nearly-unstable resonator and the first time a pulsed-wave output has been achieved. This compact hundred-millijoule-class thin-disk regenerative amplifier allows for a significant simplification of the resonator structure and thus improves the environmental suitability of the system.