High average power - high peak power cryogenic Yb:YAG lasers for pumping Ti:Sapphire and OPCPA ultrafast lasers

Ti:Sapphire and optical parametric chirped-pulse amplifier ultrafast laser systems are currently limited in average power to < 100 watts by relatively low average power pump sources. In order to achieve both high peak and average powers concomitantly, we describe the design and operation of picosecond and nanosecond Yb:YAG cryogenic laser systems currently being developed at Snake Creek Lasers (SCL) with a goal of initially producing 1 J/pulse output at 1029 nm and green output at 515 nm with energy/pulse > 0.5 J, and with a repetition rate up to 1 kHz. Yb based lasers are particularly promising because of a long upper state radiative lifetime, reducing the diode pump power needed to produce a target energy/pulse, as well as very favorable high average power scaling properties at liquid nitrogen temperature. A comparison of a number of Yb based materials including Yb: YAG, Yb:Lu2O3, and others will be presented. Using a recently developed kinetics model as well as new system design codes, we describe the average and peak power scaling of cryogenic Yb: YAG lasers as well as the limitations imposed by optically induced damage, nonlinear phase accumulation, and amplified spontaneous emission.