Cryogenic cooling system Brayton for 10 J/10 Hz Yb: YAG multi-slab based laser system at ELI-Beamlines project.

We present design and operational prototype of cryogenic cooling system based on Bryton’s cycle for 10J/10Hz Yb:YAG multi-slab laser system at ELI-Beamlines project. For efficient high energy Yb:YAG laser operation, the laser crystals are required to be cooled at cryogenic temperatures due to the material’s excellent thermo-optic and spectroscopic properties at these temperatures. In our case, the laser was designed for operation at 150 K with maximum heat load of 300 W to be removed from the laser crystals. At this temperature, the cooling system was capable of dynamically removing the waste heat arising in the Yb:YAG active medium as a result of optical pumping, while keeping the temperature stability within +/- 0.1 K.