10 mJ, 100 W, 10 kHz Hybrid Laser System Based on Rod-Type End-Pumped Yb: YAG Amplifiers Featuring Depolarization Compensation

High energy and average power picosecond laser systems are attractive for a number of applications such as OPCPA pumping, attosecond science, EUV or THz radiation generation, single shot laser marking and large area processing. However, average power scaling of such lasers presents challenges caused by thermally induced stress in the active medium in the form of depolarization, bifocusing and beam quality degradation. State of the art high power laser systems circumvent these problems by either utilizing complex amplification techniques, such as thin disc and slab, or coherent pulse combination. On the other hand, end-pumped amplifiers are still attractive for power scaling above 100W due to their simplicity. Several techniques have been proposed to minimize the issues caused by thermal aberrations in these optical setups, namely divided pulse amplification, along the side pumping or depolarization compensation [1–3].