Ag纳米颗粒增强的Ho~(3+)/Tm~(3+)共掺铋锗酸盐玻璃的2μm发光研究

采用基于传统熔融淬冷技术的热化学还原法制备了系列Ag纳米颗粒复合Ho3+/Tm3+共掺铋锗酸盐玻璃样品,研究了Ag纳米颗粒含量对玻璃2μm发光特性的影响.结果表明,Ag纳米颗粒的表面等离子体共振带位于500—900 nm,峰值位于650 nm,透射电子显微镜图像中观察到均匀分布的Ag纳米颗粒,尺寸约为5—10 nm.通过测试玻璃样品在1.7—2.3μm波段的荧光光谱发现,Ag掺杂后Ho3+离子2μm处的荧光强度得到了极大的提高,其中AgCl掺杂质量分数为0.3%时的荧光强度比未掺杂时的荧光强度增强10倍,这归因于Ag纳米颗粒的局域场增强作用.计算得到Ho3+离子的吸收截面为0.491×10-20cm-2,发射截面为1.03×10-20cm-2,当增益系数为0.2时即可实现正的增益.

Ag nanoparticles enhanced 2 um luminescences of Ho3+/Tm3+ codoped bismuth germanate glasses

The Ho³⁺/Tm³⁺ codoped bismuth germanate glasses containing Ag nanoparticles (NPs) are synthesized by a chemical reduction method based on the conventional melting-quenching technique. The effect of concentration of Ag NPs on the 2 um emission is studied. The absorption band related to the surface plasmon resonance (SPR) of the Ag NPs is located in a range from 500 to 900 nm. Transmission electron microscopic image clearly reveals homogeneously dispersed Ag NPs with the sizes ranging from 5 to 10 nm. The luminescence spectra in a range of 1.7-2.3 um are collected. With the addition mass fraction of the AgCl up to 0.3%, the intensity of emission band of Ho³⁺ ions, centered at 2.03 um, is increased by 10 folds. The enhancement of 2 um luminescence is attributed to the enhanced local field induced by SPR of Ag NPs. The calculated absorption cross section and emission cross section are 0.491× 10^-20 cm^-2 and 1.03×10^-20 cm^-2, respectively. When the gain coefficient p=0.2, the positive gain would be realised.
Keywords： Ag nanoparticles surface plasmon resonance middle infrared luminescence