Upconversion fluorescence properties of a new Er3þ/Yb3þ-codoped lead oxyfluorosilicate glass under 975 nm excitation areinvestigated. The blue, intense green and red emissions centered at 408, 529, 545, and 667nm, corresponding to the 2H9/2→4I15/2, 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively, were simultaneously observed at room temperature. The important role of Yb2O3 in upconversion intensity is observed, and the influence of Yb2O3 and PbF2 on blue, green and red emissions is compared and discussed. The dependence of upconversion intensities on excitation power and possible upconversion mechanisms are evaluated.

Upconversion luminescence characteristics of a multi-rare-earth-doped 0.05K2O-0.1ZnO-0.1BaO-0.2PbO-0.2GeO2-0.35TeO2 glass have been investigated under 976nm excitation for potential use in full colour displays.Two luminescence ions, Er3+ and Tm3+, were used as blue, green and red emitters to control the colour of the emitted light. Sensitizer ions, Yb3+, were used to increase the upconversion emission intensity. With the substitution of Er3+ for Tm3+, the intensities of the blue, green and 657nm upconversion emissions simultaneously increase.

研究了Yb3+/Er3+共掺锗碲酸盐玻璃在980nmLD抽运下的上转换发光光谱，发现随着碱金属离子半径的增大，上转换发光强度明显增强。基质玻璃的Raman光谱显示：玻璃的最大声子能量并不随碱金属氧化物之间的取代而发生变化，表明最大声子能量并不是锗碲玻璃上转换发光强度增大的原因。从玻璃无辐射跃迁的角度分析表明：最大能量声子密度的降低是影响Yb3+/Er3+共掺锗碲玻璃上转换发光强度增大的主要原因。

Er3+-doped 50SiO2-(502x) PbO-xPbF glasses were prepared. The effect of PbF content on refractive indices, densities, absorptionspectra, the Judd-Ofelt parameters Ωt (t52,4,6), fluorescence spectra and the lifetimes of I level of Er in 50SiO2-(502x) PbO-t13-2xPbF glasses were investigated, and the stimulated emission cross-section was calculated from McCumber theory. With increasing PbF2 content in the glass composition, the V parameter, fluorescence full width at half maximum (FWHM) and lifetimes of I level of Ω6 Er increase, while refractive indices and densities decrease. Compared with other glass hosts, the gain bandwidth properties of 31 Er-doped 50SiO2-50PbF glass is close to those of tellurite and bismuth glasses, and has an advantage over those of silicate, phosphateand germante glasses. The broad and flat → emission of Er around 1.55mm can be used as host material for potential broadband optical amplifier in the wavelength-division-multiplexing (WDM) network system.

Yb3+-Er3+ co-doped Na2O-GeO2-PbO glass suitable for developing optical fiber lasers and amplifiers has been fabricated. The energy transfer efficiency from Yb3+ to Er3+ was investigated in the glasses with different Yb3+-Er3+ concentration ratios and the maximum energy transfer efficiency was found to be 67% at the Yb3+-Er3+ concentration ratio of 5:1. Subsequently, the studies of upconversion emissions in the visible range were performed. An intense green together with a relatively weak red emission was observed under the excitation of 976nm diode laser. The quadratic dependence of the green emission on excitation power indicates that a two-photon absorption process occurs under a 976nm excitation. However, for the red emission the slope of log-log plot of integrated intensity versus pump power declines with increasing Yb3+ ions content, indicating it is not resulted from a biphotonic process.