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。

A highly efficient milli-joule-level Q-switched Tm,La:CaF2 laser is experimentally demonstrated. By employing an acousto-optic modulator, the diode-pumped pulsed lasers are stably operated at repetition rates ranging from 500 Hz to 10 kHz. Dual-wavelength operation of 1881.7 nm and 1888.5 nm is achieved with slope efficiency of 64.7%. Up to 1.89 mJ of pulse energy is obtained at a pulse width of 100 ns, corresponding to a peak power of 18.88 kW. These results verified that the Tm,La:CaF2 crystal could be a promising candidate for achieving highly efficient and high-energy pulsed lasers.

为了在空间限制严格的条件下，实现远距离、双波段、摆扫成像要求，采用双波段折反缩束镜、双快反镜及紧凑的单波段透镜后组，并通过优化设计，建立了一种紧凑型双波段摆扫成像光学系统。其中，双波段折反缩束镜由RC系统、CAF₂分色棱镜、及单波段透镜组组成，分别在0.6~0.9 μm及3.6~4.9 μm波段取得接近衍射极限的像质，且摆扫成像像移均控制在半个像元以内。该双波段系统中，主次镜间无透镜，可见光系统焦距为1752 mm，光学系统三维尺寸为380 mm (轴向)×Φ360，远摄比达到0.22，线遮拦比为0.34。在无遮光罩的前提下，仿真分析表明，入射角大于30°时，红外PST均小于1×10⁻⁴。且该系统加工及装调工艺成熟可控，成本较低。

3 μm波段激光是高精度外科手术的理想光源，也可作为长波中红外光参量振荡器的有效泵浦源。LD直接泵浦Er³⁺掺杂晶体是获得2.7~3 μm波段中红外激光的有效技术途径，具有成本低、结构紧凑简单等优点。由于Er³⁺ 2.8 μm激光下能级阻塞问题，一般需要高浓度掺杂，但高浓度掺杂易引起强烈的光吸收，增强了激光晶体的热效应，从而阻碍了激光功率的提升。低声子能量的氟化钙晶体特有的萤石型结构使得三价稀土离子极易形成“团簇”，将低浓度Er³⁺掺杂到氟化钙晶体中即可获得高效率的中红外激光增益介质。笔者课题组使用温度梯度法成功生长了低浓度掺杂1.3at.%Er³⁺: CaF₂激光晶体，利用LD直接泵浦获得了2.2 W的中红外激光输出，这是目前利用LD端面泵浦同类晶体中的最高中红外激光输出功率。同时，文中还对上转换泵浦方式下该晶体的2.8 μm激光特性进行了研究。实验结果表明，低浓度掺杂的1.3at.%Er³⁺: CaF₂晶体是一类具有产业化前景的中红外激光材料，有望推动长波中红外激光器向着结构紧凑、成本低的方向发展。

Optical channel waveguides with depressed cladding configurations have been produced in Nd,Gd:CaF2 laser crystals by using ultrafast laser inscription. Waveguide properties are investigated in terms of guiding behaviors and localized laser-induced lattice damages. Under an optical pump of 808 nm light, continuous-wave waveguide lasing at 1.06 μm is achieved, with a single-mode operation and a minimum lasing threshold of 98.8 mW. Furthermore, the visible emissions of Nd3+ with short wavelengths ranging from 415 nm to 550 nm and long wavelengths from 550 nm to 625 nm are observed upon 808 nm laser excitation via the up-converted process. The intensity ratios of two wavelength ranges are proved to be tunable through changing the pumping polarizations.