Yb掺杂Ca(1-x)RxF(2＋x)(R=La,Gd)激光晶体的结构与光谱性能参数的研究

Structure and Property of Yb Doped Ca_(1-x)R_xF_(2+x)(R=La, Gd) Laser Crystals

采用坩埚下降法生长了两个系列晶体3at%Yb:Ca_(1-x)R_xF_(2+x)(R=La,Gd;x=0,0.01,0.03,0.06,0.09),测试了晶体的XRD、拉曼光谱、吸收光谱、荧光光谱、荧光寿命。系统地研究了调剂离子La^(3+)、Gd^(3+)对Yb:CaF_2晶体晶格常数、拉曼光谱和光谱性能的影响规律,分析讨论了Yb^(3+)离子的结构与光谱性能之间的关系。研究结果表明,随着La^(3+)、Gd^(3+)掺杂浓度增加,晶体的晶格常数和拉曼半高宽都逐渐增大,这说明晶体膨胀和晶格振动模式种类增多。在3at%Yb:Ca_(1-x)La_xF_(2+x)晶体中,当调剂离子La^(3+)掺杂浓度为6at%时,具有最大吸收截面0.71×10-20 cm^2,荧光强度也最大;而在3at%Yb:Ca_(1-x)Gd_xF_(2+x)晶体中,当调剂离子Gd^(3+)掺杂浓度为3at%时,荧光强度最大,Gd^(3+)掺杂浓度为6at%时,具有最大吸收截面0.64×10^(-20) cm^2。共掺晶体相比于单掺3at%Yb:CaF_2晶体有更好的光谱参数。综上可知,通过调节La^(3+)、Gd^(3+)离子浓度,可以改变Yb^(3+)离子的结构,优化晶体的光谱性能。

3at%Yb：Cal_xRxF2＋x （R=La, Gd; x---0, 0.01, 0.03, 0.06, 0.09） crystals were grown by a vertical Bridgman method. X-ray diffraction （XRD）, Raman spectra, absorption spectra, fluorescence spectra and fluorescence lifetime were used to characterize the crystals. Effects of regulating ion La3＋ and Gd3＋ on lattice constants, Raman spectra and properties of Yb：CaF2 crystals were investigated. Moreover, the relationship between structure and spectral property of Yb3＋ ion was analyzed and discussed. The results show that lattice constant and Raman FWHM gradually increase with the increase of La3＋ or Gd3＋ ion doping concentration, demonstrat that lattice expands and lattice vibration modes increases, respectively. Among 3at%Yb：Cal.xLaxF2＋x crystals, the crystal doped with 6at% La3＋ has the largest absorp- tion cross section （0.71 x 10-20 cm2） and the largest fluorescence intensity. Moreover, the crystal doped with 3at% Gd3＋ has the largest fluorescence intensity. Increasing Gd3＋ content up to 6at%, the crystal has the largest absorption cross section （0.64x10.20 cmZ）. These cooping crystals have better spectral parameters than 3at%Yb：CaF2 crystals. Based onthe above results, structure of Yb3＋ ion may be changed and the crystalline spectral properties may be optimized partly through the regulation of La3＋ or Gd3＋ ions＇ concentration.