氟化钙(CaF₂)是一种良好的激光材料基质, 具有较宽的透过范围(0.125~10 µm)、良好的导热性(9.71 W/(m·K))和低非线性效应系数。在Pr:CaF₂晶体中, [Pr³⁺-Pr³⁺]团簇导致Pr³⁺离子在较低浓度下出现荧光猝灭现象。在CaF₂中共掺入La³⁺离子有可能打破[Pr³⁺-Pr³⁺]团簇。本研究通过温度梯度法(Temperature Gradient Technique, TGT), 成功地生长了一系列共掺入不同浓度La³⁺离子的Pr:CaF₂晶体。在室温下采用X射线粉末衍射、吸收光谱、荧光光谱和荧光衰减寿命对Pr, La:CaF₂晶体进行表征。Pr:CaF₂晶体共掺入La³⁺离子后仍具有立方晶体结构。³P₀→³H₆(604 nm)和³P₀→³F₂(640 nm)处的最大受激发射截面分别为1.36×10^-20和3.18×10^-20 cm², 半峰宽分别为17.0和 3.8 nm。随着La³⁺离子掺杂含量的增加, ³P₀→³H₆(604 nm)处的半峰宽从15.84增加到18.53 nm。0.6%Pr,10%La:CaF₂ (原子分数)的最大荧光寿命和光谱质量因子分别为45.82 μs和145.8×10^-20 cm²·μs。上述结果表明: [Pr³⁺-Pr³⁺]离子淬灭团被打破, Pr, La:CaF₂晶体是潜在的激光增益材料, 可应用于橙红色激光领域。

We report on a high-power Ho:YAG single-crystal fiber (SCF) laser inband pumped by a high-brightness Tm-fiber laser at 1908 nm. The Ho:YAG SCF grown by the micro-pulling-down technique exhibits a propagation loss of $0.05\pm 0.005~\text{cm}^{-1}$ at $2.09~\unicode[STIX]{x03BC}\text{m}$. A continuous-wave output power of 35.2 W is achieved with a slope efficiency of 42.7%, which is to the best of our knowledge the highest power ever reported from an SCF-based laser in the 2 $\unicode[STIX]{x03BC}\text{m}$ spectral range.

We report on a diode-end-pumped high-power and high-energy Nd:YAG single-crystal fiber laser at 1834 nm. Two 808 nm diodes injecting about 58 W pump power into the Nd:YAG fiber have generated 3.28 W continuous-wave and 1.66 W Cr:ZnSe-based passively Q-switched lasers. Slope efficiencies with respect to pump powers are 8.7% for the continuous-wave laser and 4.9% for the Q-switched laser. The extracted maximum pulse energy is about 266.9 μJ, and the corresponding maximum pulse peak power is 2.54 kW. These performances greatly surpass previous results regarding this specific laser emission because the laser gain medium in the form of fiber can significantly mitigate thermally induced power saturation thanks to its significantly reduced thermal lensing effect. Single-crystal fiber lasers show great potential for high average power, pulse energy, and peak power.