Tm^(3+)掺杂Ge-Ga-Se玻璃中红外发光特性与多声子弛豫分析

Mid-Infrared Emission and Multiphonon Relaxation in Tm^(3+)-Doped Ge-Ga-Se Glasses

用熔融急冷法制备了系列不同Tm3+掺杂浓度的Ge30Ga5Se65玻璃样品,测试了样品折射率、拉曼光谱、吸收光谱以及800nm激光泵浦下的近红外及中红外波段荧光光谱和荧光寿命。用Judd-Ofelt理论计算了Tm3+在Ge30Ga5Se65玻璃中的强度参数Ωi(i=2,4,6)、自发辐射跃迁概率A、荧光分支比β和辐射寿命τrad等光谱参数。讨论了800nm激光泵浦下掺杂1Wt%Tm3+样品在近红外1.23,1.48和1.8μm处的发光特性及各量子效率,研究了800nm激光泵浦下的样品中红外荧光特性与掺杂浓度之间的关系,计算了常温下该基质玻璃中Tm3+:3H5→3F4跃迁对于3.8μm处的多声子弛豫速率Wmp和Ge30Ga5Se65玻璃基质中多声子弛豫常数W(0)和电子-声子结合常数α值。结果表明Ge30Ga5Se65硒基玻璃较低的声子能量可以大大降低稀土离子能级间跃迁的多声子弛豫概率,从而提高中红外荧光发光效率,因此硒基玻璃作为稀土离子的掺杂基质材料对实现中红外荧光输出是非常有利的。

A series of chalcogenide glasses based on the composition Ge30Ga5Se65 （at.%） doped with the different Tm^3＋ ions were synthesized by melt-quenching technique.The refractive indexes,Raman spectra,absorption spectra,near-and mid-infrared fluorescence,and lifetimes of glass samples under 800 nm laser excitation were measured.The intensity parameters Ωi（i=2,4,6）,transition probabilities,branching ratios and radiative lifetimes have been predicted for Tm^3＋ ions in samples by using the Judd-Ofelt theory.The near-infrared emission spectra at 1.23,1.48 and 1.8 μm were observed and their quantum efficiencies were evaluated respectively in glass doped with 1 Wt% Tm^3＋-ions under 800 nm excitation.The mid-infrared fluorescence spectra were investigated with the different Tm^3＋ ion concentration under 800 nm excitation.The multiphonon relaxation rate of Tm^3＋：^3H5→^3F4 by the measured and calculated lifetimes,and the relative parameters of W（0） and α in Ge30Ga5Se65 glass were evaluated.Results show that the multiphonon relaxation rates were significantly lower than other glasses due to the lower maximum phonon energy,so the selenide glasses are promising as host materials for doping by rare earth ions and for preparation of mid-infrared optical elements.