Thermo-optical properties of Yb:YAG disks in cryogenic amplifier of high intensity femtosecond laser system

Temperature distribution in cryogenic cooled diode-pumped Yb:YAG crystal of multidisks high power laser system has been numerically calculated. Experimental investigation of dioptric power of the thermal lens and wavefront distortions by use of Shack-Hartman sensor has been performed. The obtained results are used for optimization of output beam parameters of pump channel of high intensity femtosecond laser system.