Ho^3＋掺杂Ge-Ga-S-CsI玻璃中红外发光性能研究

Mid-infrared Emission Properties of Ho^(3+)-doped Ge-Ga-S-CsI Glasses

采用熔融冷却法制备了系列不同Ho3+离子掺杂浓度的Ge-Ga-S-CsI玻璃样品,测试了样品的折射率、吸收光谱以及中红外荧光光谱和Ho3+离子5I6能级荧光寿命.应用Judd-Ofelt理论计算了Ho3+离子在该基质玻璃中强度参数Ωi(i=2,4,6)、能级跃迁振子强度fcal、自发跃迁几率Arad等光谱参数.计算了Ho3+:5I5→5I6(3.86μm)和5I6→5I7(2.81μm)跃迁的多声子驰豫速率.讨论了中红外荧光特性与Ho3+离子掺杂浓度之间的关系.结果表明,在900nm激光泵浦下观察到了2.81和3.86μm两处中红外荧光,分别对应于Ho3+:5I6→5I7和5I5→5I6跃迁,当Ho3+离子掺杂浓度从0.5wt%增加到1.0wt%时,两处中红外荧光强度都随相应增加,计算的Ho3+:5I5→5I6和5I6→5I7跃迁多声子驰豫速率分别为29s-1和34s-1.

A serial of chalcogenide glasses based on Ge-Ga-S-CsI system doped with the different Ho3＋ ions were synthesized by melt-quenching technique.The properties of glasses including refractive indexes,absorption spectra,mid-infrared emission spectra and lifetimes of 5I6 level of Ho3＋ions were measured.The Judd-Ofelt intensity parameters Ωi（i=2,4,6）,oscillator strength fcal,spontaneous transition probabilities Arad for Ho3＋ ion were calculated by Judd-Ofelt theory.Multiphonon relaxation rates of the Ho3＋∶5I5→5I6 and 5I6→5I7 in Ge-Ga-S-CsI glasses were evaluated.Effect of Ho3＋ion concentration on the fluorescence spectra was investigated.The results indicate that the fluorescence under 900 nm excitation with peak wavelength at 2.81μm and 3.86μm are due to the Ho3＋∶5I5→5I6 and 5I6→5I7 transition,respectively.The intensity of the mid-infrared fluorescence are enhanced with the Ho3＋ ion concentration increasing from 0.5wt% to 1.0wt%.Multiphonon relaxation rates are 29s-1 and 34s-1 for the Ho3＋∶5I5→5I6 and 5I6→5I7 transition,respectively.