High Power Continuous Wave Yb:YAG Composite Crystal Zigzag Slab Amplifier at Room Temperature

A 7.07-kW Yb:YAG composite crystal zigzag slab amplifier at room temperature is developed and demonstrated, the optical-to-optical efficiency is about 29.5% and the slope efficiency is 39.5%, respectively, with the pumping power of 19.98 kW and the incident seed laser power of 1.18 kW. The influence of the pump coupling efficiency, the intensity of the seed laser, and the temperature to the extracted power from the Yb:YAG slab are analyzed by simulation. The fluorescence distribution at the end face and the transmission wavefront of the Yb:YAG slab are measured, the nonuniformity of the fluorescence distribution is less than 6%, and the P-V value of the transmission wave front distortion is less than 1.6 μm.