Optimization of depolarization losses and scaling of a high average power diode pumped laser amplifier using Yb3+ doped CaF2

We compare different optimization techniques for high average-power diode-pumped solid-state laser amplifiers currently developed at the PENELOPE project. Amplified spontaneous emission and thermally induced depolarization losses are the main limiting factors besides laser induced damage. Optimizing the laser gain medium geometry and the choice of the gain medium are the key factors for highly efficient laser amplifiers.