用熔融-淬冷法制备了无稀土掺杂与Dy 3+ (0.04mol%)掺杂Ge30Ga5Se65和0.9Ge30Ga5Se65+0.1CsBr玻璃样品. 采用Judd-Ofelt理论计算了0.9Ge30Ga5Se65+0.1CsBr玻璃样品中Dy3+ 跃迁的强度系数、自发辐射几率与荧光分支比. 为了研究多声子弛豫(MPR)随温度的变化, 测试了Dy3+ 的6H11/2 能级在20～300K温度范围内的荧光寿命, 分析了Ge30Ga5Se65玻璃中声子模式与电子-声子结合强度对Dy3+ 1.72μm处荧光强度和效率的影响. 在硒化物玻璃中引入CsBr使玻璃中形成了Ga--Br键, 有效声子能量降低到268cm-1. 通过计算得到Ge30Ga5Se65与0.9Ge30Ga5Se65+0.1CsBr 样品的电子-声子结合强度分别为0.456与0.048. CsBr的引入降低了电子-声子结合强度. 声子模式与电子-声子结合强度的改变决定了MPR 的变化.
Pure and Dy3+-doped Ge30Ga5Se65 and 0.9Ge30Ga5Se65+0.1CsBr glasses were prepared by conventional melt-quenching method. The intensity parameters, spontaneous emission probability and branching ratio of Dy3+ ions in Ge30Ga5Se65+CsBr glass were calculated by Judd-Ofelt theory. The lifetime of 6H11/2 level at temperatures from 20K to 300K were measured to investigate the temperature dependence of multiphonon relaxation (MPR) rates. The influence of the local phonon mode and electron-phonon (e-p) coupling strength on the 1.72μm fluorescence efficiency of Dy3+-doped
selenide glasses was investigated. The frequency of the phonon vibration is changed to 268cm-1 due to the formation of Ga-Br bonds with the addition of CsBr to selenide glasses. The values of e-p coupling strengths in Ge30Ga5Se65 and 0.9Ge30Ga5Se65+0.1CsBr glasses are 0.456 and 0.048, respectively. It is clear that the e-p coupling strengths decrease considerably with the addition of CsBr to Ge30Ga5Se65 glass. This reduced e-p coupling together with a large change in the local phonon mode result in the change of the MPR rate.
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