激光加热基座法生长高质量Yb3+掺杂Y3Al5O12单晶光纤

单晶光纤即具有光纤形态的单晶材料, 是功能晶体材料一维化发展的重要体现。单晶光纤兼具单晶材料优异的光学性能和激光光纤散热效率高、光束质量高等特点, 有望解决传统玻璃材质激光光纤非线性效应强、热导率低等瓶颈问题, 实现激光峰值功率、脉冲能量等性能的突破。本工作采用自主研制的激光加热基座(Laser-heated Pedestal Growth, LHPG)单晶光纤炉制备了两组Ф0.2 mm×710 mm的Yb³⁺掺杂Y₃Al₅O₁₂(Yb:YAG)单晶光纤, 并对其进行了表征。制备的单晶光纤长径比大于3500, 直径波动小于5%, 且表现出一定的柔韧性; X射线摇摆曲线测试结果显示Yb:YAG单晶光纤的结晶质量与所用源棒相比有所提升; EDS线扫描结果证明单晶光纤中的Yb³⁺沿轴向呈现均匀分布。实验结果表明: 准一维化的单晶光纤具有良好的结晶质量与光学均匀性, 有望成为一种性能优异的高功率激光增益材料。

Growth of High-quality Yb3+-doped Y3Al5O12 Single Crystal Fiber by Laser Heated Pedestal Growth Method

Single-crystal fiber (SCF) is a fiber-shaped monocrystalline material, which is an important tendency for the development of low-dimensional functional crystals. Combining the excellent optical properties of bulk crystals and the high-efficient thermal dissipation as well as the high beam quality of optical fibers, SCFs are believed to solve the bottlenecks of conventional laser fibers such as unfavorable non-linear effects and poor thermal conductivities, can thus achieve higher laser peak powers and pulse energy. Here, we describe the results of synthesis and characterization of two Yb³⁺-doped Y₃Al₅O₁₂ (Yb:YAG) SCFs (Ф0.2 mm×710 mm), which were grown by a self- developed laser-heated pedestal growth (LHPG) apparatus. The prepared SCFs possess a length-to-diameter ratio greater than 3500, a diameter fluctuation less than 5%, and show high flexibility for bending. The analysis of X-ray rocking curve indicates that the crystallinity of the grown SCF is improved compared with that of the source rod. The EDS line scan shows that the Yb³⁺ ions are uniformly distributed along the axial direction. Results of these characterizations of SCFs indicate that SCFs maintains excellent crystallinity and high optical homogeneity, showing promising candidate for high-power laser applications.