Tm^3＋掺杂GeO2-AlF3-Li2O-BaF2-La2O3玻璃的光谱特性

The Optical Spectra of Tm^3＋ Doped GeO2-AlF3-Li2O-BaF2-La2O3 Glasses

用高温熔融法制备了不同Tm^3＋浓度掺杂的65GeO2—12AlF3—8Li2O-10BaF2—5La2O3-xTm2O3（x=0．5mol％，1．0mol％，2．0mol％，4．0mol％，6．0mol％）玻璃。从吸收光谱特性出发，根据Judd—Ofelt理论，计算得到了Tm^3＋离子的J—O强度参数（Ω2，Ω4，Ω6）及Tm^3＋离子各激发能级的自发跃迁几率、荧光分支比以及辐射寿命等光谱参量。在808nm波长的激发下，研究了不同Tm^3＋掺杂浓度下玻璃在～1．47μm与～1．8μm处的荧光特性，在掺杂浓度约达到．1.0mol％时，在1．8μm处的荧光强度达最大，然后随着掺杂浓度的增大，其荧光强度反而降低。作者从Tm^3＋的交叉驰豫与浓度猝灭效应解释了这一荧光强度变化的过程。

Glasses with the compositions of 65GeO2-12AlF3-8Li2O-10BaF2-5La2O3 doped with different Tm^3＋ concentration （0.5,1.0,2.0,4.0,6.0 mol % ） were fabricated by conventional melting method. According to the absorption spectra and the Judd-Ofelt theory, the J-O strength parameters（Ω2, Ω4,Ω6） were calculated, by which the radiative transition probabilities, branching ratios and radiative lifetimes were obtained. The infrared emission spectra （with 808nm LD excitation） at -- 1.47 μm and --1.8 μm of various concentration Tm^3＋ -doped glasses were studied. The emission intensity at ～ 1.8 μm reaches to the maximum when the Tm^3＋ -doping concentration is near to be 1.0 mol% and then decreases at higher concentration. The mechanism of the change of the fluorescence intensity was explained from the cross-relaxation effect and the concentration quenching of Tm^3＋ effect.