We demonstrate a high-power InnoSlab amplifier based on a multi-segmented composite ytterbium-doped yttrium aluminum garnet (Yb:YAG) crystal. A systematic comparison was performed of the laser amplification output performance of multi-segmented and conventional Yb:YAG crystals to demonstrate the feasibility of using gain media with multiple doping concentrations in InnoSlab laser amplifiers. We achieved an amplified output of 245 W based on the multi-segmented composite Yb:YAG crystal InnoSlab amplifier, with a beam quality of M2 = 1.21 × 1.25 and an optical-to-optical efficiency of 38.9%. Thanks to the unique doping structure of the composite crystal, compared to homogeneous dopant crystals, the average output power, optical-to-optical efficiency and beam quality were significantly improved. Exceptional output power stability with a root mean square fluctuation of 0.11% and pointing stability of approximately 7.5 μrad were achieved.
