Optimized Growth and Laser Application of Yb:LuAG Single-Crystal Fibers by Micro-Pulling-Down Technique

Single-crystal fibers (SCFs) have a great application potential in high-power lasers due to their excellent performance. In this work, high-quality and crack-free Yb3+:Lu3Al5O12 (Yb:LuAG) SCFs were successfully fabricated by the micro-pulling-down (μ-PD) technology. Based on laser micrometer X-ray Laue diffraction results, these Yb:LuAG less than 5% diameter fluctuation good crystallinity along axial direction. More importantly, distribution of Yb ions is proved be uniform electron probe microanalysis (EPMA) scanning microscope (SEM). experiment, continuous-wave (CW) output power using 1 mm single-crystal fiber determined 1.96 W, at central wavelength 1047 nm, corresponding slope efficiency 13.55%. Meanwhile, applying 3 SCF, we obtain 4.7 W CW 1049 nm with 22.17%. The beam quality factor M2 1.1 both conditions, indicating optical grown fiber. Our results show that SCF solid-state gain medium for μm lasers.