摘要:
用高温熔融法制备了Tm2 O3掺杂浓度为0.25,0.5,0.75,1,1.25,1.5 mol%的40 GeO2-35TeO2-15PbO-5Al2O3-2.5CaO-2.5SrO锗碲酸盐玻璃.热学性质测试表明该玻璃的转变温度为446?C,没有析晶峰.玻璃的最大声子能量约为750 cm?1.利用Judd-Ofelt理论计算了Tm3+的Judd-Ofelt参数?t(t =2,4,6)、不同浓度下Tm3+离子各激发态能级的自发辐射概率、荧光分支比以及辐射寿命等参数.采用808 nm波长抽运源测试了Tm3+离子的荧光光谱.发现掺杂浓度为1 mol%时约1.8μm处的荧光强度最强.根据McCumber理论计算了3F4→3H6的发射截面,其峰值发射截面为6.5×10?21 cm2.根据速率方程计算了玻璃中OH引起的Tm3+的3 F4能级的无辐射弛豫速率,随着Tm3+浓度增加, OH对3 F4能级的猝灭速率增加.这种玻璃有望研制成一种新型的约2μm的激光玻璃材料.
Abstract:
Tm2O3-doped 40GeO2-35TeO2-15PbO-5Al2O3-2.5CaO-2.5SrO glasses with different Tm3+ ion concentrations are fabricated by conventional melt-quenching method. From the measurements of thermal properties it follows that the glass transition temperature is 446 ?C and crystallization peak does not exist. The maxmium phonon energy of the host is ～ 750 cm?1. The Judd-Ofelt strength parameter ?t (t = 2, 4, 6), the radiative transition probalities, the branching ratios and the radiative lifetime are calculated according to Judd-Ofelt theory. The emission spectra of Tm3+doped glasses with different Tm2O3 concentrations are measured under the excitation by an 808 nm diode laser. The result shows that the emission intensity at ～ 1.8 μm reaches a maximal value when the Tm2O3-doping concentration is 1 mol% and then it decreases with the further increase of Tm2O3-doping concentration. The emission cross section of 3F4 → 3H6 is calculated based on the McCumber theory. The peak emission cross-section is 6.5 × 10?21 cm2. The non-radiative transition rate of 3F4 caused by OH is calculated quantitatively by rate equation. The results indicate that the germanate-tellurite glass is a new candidate for mid-infrared laser application.
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