High-efficiency Yb:YAG laser with a gradient-doped crystal at room temperature

A Yb:YAG crystal with a gradient dopant of 0.11∼1.36 at.% Yb³⁺ is designed, and its laser performance is demonstrated in a laser diode single-end pumped configuration. Compared with the homogeneous-doped crystal, the laser performance of the gradient-doped crystal is significantly improved due to the reduced thermal effects. The maximum output power of 60.2 W with the maximum optical-to-optical conversion efficiency of 53.2% is obtained in continuous-wave operation at 1030 nm, and the corresponding slope efficiency is 61.4%. The results show that the gradient-doped Yb:YAG crystal has advantages of mitigating thermal effects and excellent gain performance, and it is proven that the gradient-doped Yb:YAG crystal is effective for high-efficiency output at room temperature.