Thermal challenges in high power optical parametric amplifiers

In contrast to conventional laser amplifiers, optical parametric amplifiers (OPAs) offer an enormous gain bandwidth that can reach or even exceed one optical octave supporting extremely short pulses. At the same time, OPAs have the reputation to be scalable to high average powers due to the lack of energy storage in the nonlinear medium. In particular, pumping OPAs with pulsed high average power fiber lasers enabled the current record level of more than 20 W of output power. However, thermal effects similar to those observed in conventional lasers will ultimately limit average power scaling of OPAs. In this contribution, experimental and numerical results on thermal effects in high average power OPAs are presented.