不同频率声子参与的氟玻璃中Ho3+离子的多声子弛豫

测量了掺Ho3+离子的氟玻璃的吸收光谱,激发光谱、发射光谱,10K～660K不同温度下的激发态寿命及氟玻璃的拉曼光谱.根据Judd-ofelt理论计算了辐射跃迁几率,进而计算了不同温度下的无辐射联迁几率.利用Huang-Rhys多声子跃迁理论分析了无辐射跃迁几率与温度的关系.在分析中考虑到不同频率声子的参与,并考虑到黄昆因子,得到与实验很好的符合.由理论和实验的拟合中估计了黄昆因子的大小,讨论了黄昆因子在无辐射跃迁中的作用.

MULTIPHONON RELAXATION OF Ho~(3+) INVOLVING PHONONS OF DIFFERENT FREQUENCIES IN FLUORIDE GLASS

Optical absorption, emission and excitation spectra, lifetime of 6S2 state from 10K to 660K for Ho3+ ions in fluoride glass and the Raman spectrum of fluoride glass were measured. The radiative transition probabilities of Ho3+ in fluoride glass were calculated from its absorption spectrum on the basis of Judd-Ofelt theory. The nonradiative transition probabilities of 5S2 state from 10K to 660K were determined by the calculated radiative transition probability and the mesured lifetimes of 5S2 state at different temperatrues. With phonon energy determined from Raman spectrum, it is found that if only one kind of phonon were considered there could be no way to conform with the experimental results, while if phonons with two different frequncies, as well as the influnce of Huang's factor are taken into account, fairly good fitting could be obtained.The Huang's factor is estimated from the fitting of the theory to the experimental results. The effect of Huang's factor on nonradiative transition rates is discussed.