Er^(3+)-Yb^(3+)-Tm^(3+)共掺CdF_2:PbF_2基玻璃中的荧光特性及其上转换机制

Luminescence Properties and Up-Conversion Mechanism of Er^(3+)-Yb ^(3+)-Tm ^(3+)Co-Doped CdF_2:PbF_2-Based Glass

在 98 0nm半导体激光激发下 ,在Er3+ Yb3+ Tm3+ 共掺玻璃样品中得到了如下的 5条较强的上转换荧光带 ,分别是近红外 (80 0nm) ,红 (6 4 5nm) ,绿 (5 4 5和 5 2 5nm) ,蓝 (4 80nm)及紫 (4 0 7nm)。与Er3+ Yb3+ 共掺样品相比 ,Tm3+ 的加入使得 4 80nm的蓝光显著增强 ,这应与Tm3+ 特殊的能级结构有关 ;荧光强度随激发功率变化的双对数曲线表明 4 80nm蓝光发射是双光子激发过程 ,为两个Yb3+ 的合作上转换敏化发光 ,随着激发功率的增加 ,4 80nm荧光的logI logP曲线的斜率将变小 ,逐渐向下“弯曲”。作者详细的分析了各条荧光带的上转换机制 ;并用速率方程讨论了稳态情况下 4 80nm蓝色上转换荧光强度随激发功率变化的关系 ,其结果与实验一致。

Under 980 nm excitation, we obtained five intense up-conversion luminescence bands in Er 3+-Yb 3+-Tm 3+co-doped CdF 2:PbF 2-based glass as follows: infrared(800 nm), red(645 nm), green (545 nm and 525 nm), blue(480 nm ) and violet(407 nm) up-conversion luminescence. With the addition of Tm 3+, the intensity of 480 nm blue luminescence increased notably compared with that of co-doped Yb 3+-Er 3+ sample, which attributed to Tm 3+ special energy level structure; logI-logP plot of the luminescence intensity versus pump power shows that 480 nm luminescence emission is a two-photon excitation process induced by the cooperative up-conversion between two Yb 3+ ions and the slope of logI-logP plot decreases gradually with increasing pump power and shows a tendency to bend down. The up-conversion mechanism is analyzed in detail under 980 nm semiconductor laser excitation; the dependence of 480 nm up-conversion luminescence intensity on the pump power under the steady states is discussed by using rate equation and the results agree well with the experiments.