Abstract The Na5Y9F32 fluoride single crystals tri-doped with ∼1 mol% Ho3+/∼1 mol% Er3+, and various concentrations of Pr3+ (0, 0.5, 0.8 and 1.0 mol%) were successfully grown by a modified Bridgman method. The absorption, Raman, emission spectra and fluorescence decay curves of Pr3+/Ho3+/Er3+ tri-doped Na5Y9F32 single crystals were studied systematically. The intensity parameters (Ω2 = 1.96 × 10−20 cm2, Ω4 = 1.66 × 10−20 cm2, Ω6 = 1.46 × 10−20 cm2) of Er3+ ions and emission cross-sections at ∼2.7 μm (1.76×10−20 cm2) and ∼2.9 μm (1.34×10−20 cm2) were calculated according to the measured absorption spectra. The emission intensities at ∼2.7 μm of Er3+: 4I11/2 → 4I13/2 and ∼2.9 μm of Ho3+: 5I6→5I7 were enhanced gradually as increase of Pr3+ concentrations from 0 to 1.0 mol% under excitation of 800 nm laser diode (LD). However, the ∼2.0 μm of Ho3+: 5I7→5I8 and ∼1.5 μm of Er3+: 4I13/2 → 4I15/2 were gradually reduced. The introduction of Pr3+ can greatly reduce the lifetimes of Er3+: 4I13/2 and Ho3+: 5I7. The energy transfer from Er3+: 4I13/2 to Ho3+: 5I7 level and depopulating Er3+: 4I13/2 and Ho3+: 5I7 levels under the action of Pr3+ ions are responsible for the enhancement of ∼2.7 and ∼2.9 μm emissions. The Pr3+/Ho3+/Er3+ tri-doped Na5Y9F32 single crystal may become a new choice for ∼3.0 μm mid-infrared solid-state laser.

中文翻译：

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通过引入 Pr3+ 离子增强 Ho3+/Er3+ 共掺杂 Na5Y9F32 单晶的中红外发射

摘要 Na5Y9F32 氟化物单晶用~1 mol% Ho3+/~1 mol% Er3+ 和不同浓度的Pr3+（0、0.5、0.8 和1.0 mol%）通过改进的Bridgman 方法成功生长。系统研究了Pr3+/Ho3+/Er3+三掺杂Na5Y9F32单晶的吸收、拉曼、发射光谱和荧光衰减曲线。Er3+ 离子的强度参数（Ω2 = 1.96 × 10−20 cm2，Ω4 = 1.66 × 10−20 cm2，Ω6 = 1.46 × 10−20 cm2）和发射截面在∼2.7 μm (1.76×10−20 cm2) ) 和 ~2.9 μm (1.34×10−20 cm2) 根据测量的吸收光谱计算。在 800 nm 激光二极管 (LD) 激发下，随着 Pr3+ 浓度从 0 增加到 1.0 mol%，在~2.7 μm Er3+: 4I11/2 → 4I13/2 和~2.9 μm Ho3+: 5I6→5I7 处的发射强度逐渐增强）。然而，约 2.0 μm 的 Ho3+：5I7→5I8 和~1.5 μm 的 Er3+: 4I13/2 → 4I15/2 逐渐减少。Pr3+的引入可以大大降低Er3+：4I13/2和Ho3+：5I7的寿命。在 Pr3+ 离子的作用下，从 Er3+: 4I13/2 到 Ho3+: 5I7 能级和减少 Er3+: 4I13/2 和 Ho3+: 5I7 能级的能量转移导致~2.7 和~2.9 μm 发射的增强。Pr3+/Ho3+/Er3+ 三掺杂Na5Y9F32 单晶可能成为~3.0 μm 中红外固体激光器的新选择。