Wavefront improvement in Nd: YAG zigzag slab amplifier by optimizing pump beam configuration and mechanical stress

To optimize the wavefront quality in end-pumped Nd: YAG slab amplifier systems, the effects of three important parameters- pump beam configuration, torque-induced stress during slab chamber assembly, and increased convective heat-transfer coefficient- were optimized. As a result, the fluctuating optical path difference decreased from over 8.7 μm to 2 μm at pump power of 2.4 kW. Also, when the BQ parameter was calculated at a pump power of about 3 kW, it decreased from 12.22 to 4.35 in configurations 1 and 2. The optical path difference was evaluated using interferometric techniques, which provide high sensitivity for optimizing the parameters of the zigzag slab-pumping module. The optimized amplifier module results are in good agreement with the experimental observations, clearly validating the proposed approach.