The Tm:CaF₂ single-crystal fibers were successfully grown by modified temperature gradient technique method. The J-O intensity parameters, spontaneous radiative transition rates, radiative lifetimes and fluorescence branching ratios of Tm³⁺ were calculated with Judd-Ofelt theory. A systematic study of the fluorescence characteristics has been carried out. Simulated emission cross-sections of the ³F₄ → ³H₆ transition were calculated to be 6.68×10⁻²¹ cm⁻² and 4.65×10⁻²¹cm⁻² for crystal doped with 3 at.% and 4 at.% Tm³⁺. The 64.4% slope efficiency with output power of 2.23W was achieved in 3 at.% Tm:CaF₂ single-crystal fiber. The slope efficiency decreased to 44.5% and maximum output power decreased to 1.65W in 4 at.% Tm:CaF₂ single-crystal fiber. Obtained results show that Tm-doped CaF₂ single-crystal fibers are promising materials for IR laser action generation.

中文翻译：

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LD抽运的Tm ³⁺：CaF ₂单晶纤维的高效〜2 µm CW激光操作

通过改进的温度梯度技术成功地生长了Tm：CaF ₂单晶纤维。用Judd-Ofelt理论计算了Tm ³⁺的JO强度参数，自发辐射跃迁速率，辐射寿命和荧光支化比。已经进行了荧光特性的系统研究。对于掺有^3at。％和4at。％Tm的晶体，计算出的³ F ₄ → ³ H ₆跃迁的模拟发射截面为6.68×10 ^-21 cm ^-2和4.65×10 ^-21 cm ^-2。³⁺。在3 at。％Tm：CaF ₂单晶纤维中，输出功率为2.23W，斜率效率为64.4％。在4 at。％Tm：CaF ₂单晶纤维中，斜率效率下降到44.5％，最大输出功率下降到1.65W 。所得结果表明，掺Tm的CaF ₂单晶纤维是产生IR激光作用的有前途的材料。