中文摘要：

采用坩埚下降法生长了Tm^3＋掺杂浓度为0．45％，0．90％，1．63％与3．25％（摩尔分数，X）的LiLuF4单晶．测试了样品的电感耦合等离子体原子发射光谱（ICP-AES）、X射线衍射（XRD）谱、吸收光谱（1400—2000nm），并且分析比较了808nm半导体激光器（LD）激发下荧光光谱．结果表明：当Tm^3＋的浓度从0．45％变化到3．25％时，1800nm处的荧光强度呈现了先增后减的趋势，当掺杂浓度约为0．90％时达到最大值，而位于1470nm处的荧光强度则呈现了相反的趋势．Tm^3＋：^3F4能级的荧光衰减寿命随着掺杂浓度的增加不断减小．1800nm处的这种荧光强度变化归结于Tm^3＋离子间的交叉驰豫效应（^3H6，^3H4→^3F4，^3F4）和自身的浓度猝灭效应．同时计算得到了浓度为0．90％的样品在1890nm处的最大发射截面为0．392×10^-20cm^2．并且根据Judd—Ofelt理论所得寿命和测定的荧光寿命计算得到了^3F4→^3H6的最大量子效率约为120％．

英文摘要：

LiLuF, single crystals doped with molar fractions of 0.45%, 0.90%, 1.63%, and 3.25% （x, molar fraction） Tm^3＋ ions were fabricated by an improved Bridgman method. Absorption spectra in the 400-2000 nm region of the crystals were measured. The emissions from 1400 to 2000 nm under excitation of an 808-nm laser diode （LD） were carried out and compared. Two emission bands at 1470 and 1800 nm were observed. First, the emission intensity at 1800 nm increased with the increase in Tm^3＋ concentration, reaching a maximum value when the Tm3. concentration was ca 0.90%. Thereafter, it decreased considerably as the Tm^3＋ doping levels further increased to 3.25%. However, the emission intensity at 1470 nm showed the contrary tendency to that at 1800 nm. It was found that the 1800-nm emission lifetime of the Tm3＋：3F, manifold systematically decreased with an increase in Tm^3＋concentration. The trend in the fluorescent intensity change can be explained by the cross-relaxation （3H8, 3H4→3F4, 3F,） between the Tm3. ions and the concentration quenching effect of Tm^3＋. Meanwhile, the emission cross-section was calculated, providing a maximum of 0.392×10^-20 cm2 at 1890 nm for the 0.90% doped sample. Based on the measured lifetime and calculated radiative lifetime, the largest quantum efficiency between Tm3. ions reached -120%.