One kilowatt high-beam-quality and highly-efficient diode-pumped Nd:YAG rod laser

We have achieved a high-quality beam generation with highly efficient quasi-cw Nd:YAG laser over 1-kW with a novel side-pumping configuration using micro-lens free diode-stacks as a part of "Advanced Photon Processing and Measurement Technologies" program. We have demonstrated a power scaling of Nd:YAG rod laser over 1-kW while maintaining high-beam-quality and high-efficiency by cascaded-coupling of two identical bifocusing compensation resonators. Laser power of 1050W was obtained with the beam quality of M 2 = 8 at the electric-to-optical efficiency of 23%. In this work, we also demonstrated the focusing ability of less than 50 μm diameter on the focal plane by using a f50 mm lens (N.A. 0.2).