Thermal and Stress Characterization of Various Thin-disk Laser Configurations at Room Temperature

Operational performance of kilowatt-class thin-disk ceramic and single crystal Yb:Yag lasers is presented. High pump power is applied to various thin-disk assemblies on two different test beds. The assemblies are composed of ASE caps, 200μm gain media, and heat sinks made of SiC, sapphire, or diamond. A novel mounting and cooling process is described. FEA modeling of the assemblies is performed using COMSOL stress and thermal computations to understand and quantify thermal and stress effects on beam quality and laser output power. Under increased pump power, the thin-disk can deform 5-10 μm in the center, destroying cavity stability. This is observed experimentally. The results of this work indicate that a single thin-disk laser could simultaneously produce high beam quality and high power if novel thermal management techniques are employed.