Er^(3+)掺杂Ge-Ga-S-KBr硫卤玻璃的中红外发光和多声子弛豫的研究

Mid-infrared Emissions and Multiphonon Relaxation in Er^(3+)-doped Chalcohalide Glasses

为了获得能输出中红外荧光的理想基质玻璃,用熔融急冷法制备了系列不同Er3+离子掺杂浓度的Ge-Ga-S-KBr硫卤玻璃,测试了样品折射率、吸收光谱、中红外荧光光谱.通过吸收光谱计算了Er3+离子吸收谱线的振子强度,应用Judd-Ofelt理论计算分析了Er3+离子在Ge-Ga-S-KBr硫卤玻璃中的强度参量Ωi(i=2,4,6)、自发辐射跃迁几率A、荧光分支比β等光谱参量.研究了808nm激光抽运下样品中红外荧光特性与掺杂浓度之间变化关系,并用Futchbauer-Ladenburg公式分别计算了2.8μm处的受激发射截面.结果表明,在808nm激光抽运下观察到了2.8μm中红外荧光,对应于Er3+:4I11/2→4I13/2跃迁,当Er3+离子掺杂浓度从0.4wt%增加到1.0wt%时,中红外荧光强度相应增加,计算的Er3+:4I11/2能级的多声子驰豫速率为37s-1.

In order to output the ideal infrared fluorescence matrix glass,a serial of chalcogenide glasses based on Ge-Ga-S-KBr system doped with different Er3＋ concentrations are synthesized by a melt-quenching technique.The refractive indexes,absorption spectra,mid-infrared emission spectra of samples are measured.The oscillator strengths of absorption lines of Er3＋ ions are calculated using the absorption spectra.The intensity parameters（Ωi,i=2,4,6）,transition probabilities（A）,branching ratios（β） are predicted for Er3＋ ions in the samples using the Judd-Ofelt theory.The mid-infrared emission properties are investigated for the samples with the different Er3＋ concentrations under 808 nm laser excitation.The 2.8 μm-emission cross-section is calculated using the theory of the Futchbauer-Ladenburg.The results indicate that the fluorescence under 808 nm excitation with peak wavelength at 2.8 μm is due to the Er3＋∶4I11/2→4I13/2 transition.The intensity of the mid-infrared fluorescence is enhanced by increasing the concentration of the Er3＋ from 0.4 wt% to 1.0 wt%.Multiphonon relaxation rate is estimated to be 37 s-1 for the Er3＋∶4I11/2 level.