Key Laboratory of Materials for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China.
J Phys Chem A. 2011 Jun 23;115(24):6488-92. doi: 10.1021/jp201913q. Epub 2011 May 25.
A detailed characterization of structural analysis and energy transfer (ET) process in Tm(3+) doped germanate glasses has been presented. The thermal stability and Raman spectroscopic analysis of the host glass structure has been discussed. It is observed that replacing GeO(2) by Ga(2)O(3) resulted in decreasing of glass transition temperature and largest phonon energy. Increasing concentration of Ga(2)O(3) decreases the density of cross-linking of the germanate glass network, and weaker Ga-O bonds result in lower phonon energy. The influences of the concentrations of Ga(2)O(3) and the glass structure on the ET have also been analyzed. The extended overlap integral method is used to calculate the microparameters of the energy transfer and the critical distance. The results show that the transference Tm → Tm ((3)H(4), (3)H(6) → (3)H(6), (3)H(4)) energy migration is not phonon dependent in the quasiresonant processes, while the cross relaxation Tm → Tm ((3)H(4), (3)H(6) → (3)F(4), (3)F(4)) is a multiphonon mechanism dominated by one-phonon creation (∼96%). It is demonstrated that the stretching frequencies and the ET processes become lower when increasing the concentration of Ga(2)O(3).
详细描述了掺铥锗酸盐玻璃中的结构分析和能量转移（ET）过程。讨论了基质玻璃结构的热稳定性和拉曼光谱分析。观察到用 Ga2O3 取代 GeO2 会降低玻璃转变温度和最大声子能量。增加 Ga2O3 的浓度会降低锗酸盐玻璃网络的交联密度，较弱的 Ga-O 键会导致较低的声子能量。还分析了 Ga2O3 浓度和玻璃结构对 ET 的影响。采用扩展重叠积分法计算了能量转移的微参数和临界距离。结果表明，在准共振过程中，Tm→Tm((3)H4，(3)H6→(3)H6，(3)H4)能量迁移与声子无关，而交叉弛豫 Tm→Tm((3)H4，(3)H6→(3)F4，(3)F4)是由单声子产生主导的多声子机制（约 96%）。结果表明，随着 Ga2O3 浓度的增加，拉伸频率和 ET 过程会降低。
