Rare-earth-doped single-crystal fibers are promising for use in developing high-power lasers due to their improved thermal management and excellent optical properties. In this work, Er-doped CaF 2 single-crystal fibers of good optical quality were successfully grown by a modified temperature gradient technique method. For the characteristic clustering effect of trivalent rare earth ions within fluorite crystals, a high-efficiency 2759.1 nm laser was obtained in a 1 at.% Er-doped CaF 2 crystal fiber. Moreover, even in an extremely lightly doped crystal fiber with a concentration of 0.5 at.%, a continuous-wave (CW) 2758.2 nm laser with a slope efficiency of 20% was achieved. Without the cascade lasing, a ~2.8 μ m CW laser operation pumped by a laser diode was first demonstrated in the case of a Er 3+ doping concentration below 1 at.%. The results suggest that Er-doped CaF 2 single-crystal fibers are promising for mid-infrared lasers.

中文翻译：

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掺Er极轻的CaF 2单晶纤维中的高效2.76μm连续波激光器

稀土掺杂的单晶纤维由于其改善的热管理和出色的光学性能而有望用于开发高功率激光器。在这项工作中，通过改进的温度梯度技术方法成功地生长了具有良好光学质量的掺Er CaF 2单晶纤维。对于萤石晶体中三价稀土离子的特征聚集效应，在掺有1at。％Er的CaF 2晶体光纤中获得了高效的2759.1 nm激光。而且，即使在浓度为0.5原子％的极轻掺杂的晶体光纤中，也可以实现斜率效率为20％的连续波（CW）2758.2nm激光器。在没有级联激射的情况下，在Er 3+掺杂浓度低于1 at。％的情况下，首次证明了由激光二极管泵浦的〜2.8μm CW激光操作。