Yb：YAG晶体中的荧光浓度猝灭现象

在Ｙｂ：ＹＡＧ晶体中发现浓度猝灭现象，对猝灭机制进行了分析研究，指出退火前晶体的荧光浓度猝灭现象主要由Ｙｂ＾２＋、色心和由此产生的晶格畸变所致高掺杂浓度时痕量稀土杂质离子的存在也将导致浓度猝灭，确定了Ｙｂ：ＹＡＧ晶体中Ｙｂ＾３＋的理想掺杂浓度。

CONCENTRATION QUENCHING IN Yb: YAG CRYSTAL

The concentration quenching on active ions in laser crystals has effects on theiroptical and laser properties, so it is necessary to study. Recently, Yb3+ doped solid- state materials are attractively used as gain media of high efficiency, high power laserwith the development of InGaAs laser diode. Among the numerous Yb3+ doped crystals,Yb: YAG has exhibited enormous potential for high efficiency and high power lasersbecause of its excellent optical and spectroscopic performances, high thermal conductivity and tensile strength. Since Yb3+ possesses only two relevant electronic states--the2F7/2, ground state and 2F5/2 excited-separated by about 10, 000cm-1, the concentrationquenching is nonexistent in Yb: YAG in principle. However, the measurements onfluorescence lifetimes of unannealing Yb: YAG with different doping level demonstrated that there were concentration quenching in Yb: YAG crystal for Yb3+doping concen-tration of more than 10at. %. This phenomenon was studied, and the decrease of fluorescence lifetime is attributed to Yb2+, which results in color center and lattice distortion of Yb: YAG. Trace impurity ions such as Er3+ and Tin3+ are detected by means ofICP and X-ray excited emission spectrum, which are also responsible for the concentration quenching at high Yb3+ doping level. The optimal Yb3+ doping level in Yb: YAGcrystal is less than 20at. %, which is determined by the fluorescence lifetime measurement.