Spectral Properties of Tm^（3＋）-Doped BaY2F8 Crystals Grown by Temperature Gradient Method

采用温度梯度法成功生长出BaY2F8晶体和Tm3＋：BaY2F8晶体。测试了Tm3＋：BaY2F8晶体的室温吸收光谱和室温、低温荧光光谱;根据Judd–Ofelt理论,拟合出晶体场强度参数i（i=2,4,6）为：2=0.364 1×10–20cm2,4=5.750 9×10–20cm2,6=2.533 9×10–20cm2。计算并分析了Tm3＋：BaY2F8晶体各激发能级的自发辐射跃迁几率、荧光分支比、荧光寿命和积分发射截面积等光谱参量,从计算的结果可以看出3F4→3H6跃迁有较大的荧光寿命、积分发射截面,易于实现人眼安全波段的激光震荡。结合室温和低温的荧光发射谱,定性阐述了随着温度的降低,荧光发射峰的强度增强,并且主要发射峰的半峰宽变窄。

Spectral Properties of Tm3+-Doped BaY2F8 Crystals Grown by Temperature Gradient Method

The laser crystal Tm3+ :BaY2F8 and BaY2F8 were grown by temperature gradient method. The absorption and emission spectra of Tm3+ :BaY2F8 crystal at room temperature were measured and studied. Based on Judd–Ofelt theory, the intensity parameters of i (i = 2, 4, 6) have been fitted and values are: 2 = 0.364 1 × 10 –20 cm 2 , 4 = 5.750 9 × 10 –20 cm 2 , 6 = 2.533 9 × 10 –20 cm 2 . The val- ues of radiative probabilities, radiative lifetime and integrated emission cross-sections of Tm3+ -doped BaY2F8 crystal were calculated. The results indicate that the eye-safe laser can be obtained because of the larger radiative lifetime and integrated emission cross-section of the 3 F 4 → 3 H 6 transition. The emission spectra at low temperature show that the intensity of the emission peak in- creases with decreasing temperature, while the FWHM becomes narrower.