Nanoparticle (NP) research has emerged as an advanced research field in the twenty-first century. The plasmonic properties of noble-metal NPs have attracted considerable interest from domestic and foreign researchers. The luminous efficiency of rare-earth ions in a glass matrix is considerably improved by the introduction of metal NPs. Meanwhile bismuthate glass is an ideal substrate for fiber amplifier fabrication given its wide infrared (IR) transmission area, strong ability to dissolve rare-earth ions, low phonon energy, and high refractive index.  Its application as a matrix material for Er3+ ions should be studied given these properties.  Recently, many studies have focused on the effect of Ag NPs on the emission properties of rare-earth-ion-doped glass under visible and near-IR wavelengths. However, few studies have focused on the enhancement of MIR emission by metal NPs. Hence, studying the effect of Ag NPs on the emission properties of Er3+-doped bismuth germanate glass under 2.7 μm emission is essential. 
     Recently, Jia Xiaomeng, a graduate student in the laboratory, used melt quenching to control the deposition of Ag nanoparticles in Er3+ and Ag nanoparticle co-doped bismuthate glass, analyzed the Er3+ luminescence enhancement mechanism, and studied the influence of metallic Ag NPs on the luminescence of Er3+/Ag co-doped bismuth germanate glass (BGN) samples at 2.7μm intensively. The results illustrate that the absorption spectrum shows that the SPR peak of Ag nanoparticles is in the range of 575-590 nm. It can be seen from the fluorescence spectrum that, the fluorescence intensity of Er3+ reaches a maximum at 2.7 μm when the AgCl concentration is 1.5 mol%, and the fluorescence intensity is enhanced by about 1.6 times compared with the glass sample without AgCl, and its fluorescence lifetime is 0.902ms. The maximum stimulated emission cross section σem of the Er3+:4I11/2→4I13/2 transition at 2.7μm is 1.36×10-19 cm2. This new type of nanocomposite material is expected to be a potential material for the gain media of lasers, optical displays and optical memory devices. The scientific research results are currently published in “The Journal of Optical Materials Express”, 2018, 8, 1625-1632. 

Fig. 3 Fluorescence spectra of BGN2 samples. The spectra were acquired under excitation at (a) 2.7 μm; (b) 527, 548, and 661 nm; and (c) 1.5 μm. (d) Energy level diagram of Er3+ ions.

 Paper link: https://doi.org/10.1364/OME.8.001625