Wang Guo-Nian

Blue Upconversion Luminescence in Tm3+/Yb3+-Codoped Lead Chloride Tellurite Glass

The thermal stability, Raman spectrum and upconversion properties of Tm^(3+)/Yb^(3+) co-doped new oxyfluoride tellurite glass are investigated. The results show that Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass possesses good thermal stability, lower phonon energy, and intense upconversion blue luminescence. Under 980-nm laser diode (LD) excitation, the intense blue (475 nm) emission and weak red (649 nm) emission corresponding to the 1G4 -> 3H6 and 1G4 -> 3F4 transitions of Tm^(3+) ions respectively, were simultaneously observed at room temperature. The possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass can be used as potential host material for the development of blue upconversion optical devices.

Thermal Stability and Spectroscopic Properties of Yb:Zinc–Tungsten–Tellurite Glass

New multi-component Yb:zinc–tungsten–tellurite glasses (70TeO2-(20-x) ZnO-xWO3-5La2O3-2.5 K2O-2.5 Na2O-1.0 Yb2O3 (x = 0, 15 mol%) have been presented. Thermal stability and spectroscopic properties of Yb3+ ions have been measured. The results show that TZW2 glass (x = 15 mol%) has thermal stability (Tx−Tg>160 degrees C with Tx being the onset crystallization temperature and Tg the glass transition temperature) better than TZN glass and that the stimulated emission cross-section of 1.32 pm2 for the 2F5/2→2F7/2 transition is higher than other laser glasses (QX, ADY, LY and FP), with the measured fluorescence lifetime of 0.93 ms and the broad fluorescence effective linewidth of 74.5 nm. Evaluated from the good potential laser parameters, TZW2 glass with both the minimum pump intensity (0.92 kW/cm2) and gain parameter (1.23 pm2ms) is promising for miniature solid fibre lasers or high-peak power lasers, as well as tunable lasers.

Fluorescence Lifetime Increasing with F− Ions into Ytterbium-Doped Germanium–Lead–Tellurite Glasses

The effects of F− ions in a germanium–lead–tellurite glass system on the spectral and potential laser properties of the Yb3+ are investigated. The absorption spectra, lifetimes, the emission cross-sections and the minimum pump intensities of the glass system with and without F− ions have been measured and calculated. The results show that the fluorescence lifetime and the minimum pump intensity of Yb3+ ions increase evidently, which indicates that germanium–lead–oxyfluoride tellurite glass is a promising laser host matrix for high power generation. FT-IR spectra were used to analyse the effect of F− ions on OH− groups in this glass system. Analysis demonstrates that addition of fluoride removes the OH− groups and results in improvement of fluorescence lifetime of Yb3+.

Effect of PbS on Properties of the Er3+-doped TeO2-based Glasses

Novel Er3+ doped TeO2-based glasses containing PbS have been prepared in argon atmosphere in carbon crucibles. The thermal analysis and spectroscopic properties of those glasses have been considered in terms of sulfide influence. Judd–Ofelt theory is introduced to calculate the bandwidth and the emission cross-section. The results demonstrate that addition of PbS into tellurite glasses results in increasing bandwidth from 71.8 to 78.4 nm, for improving emission cross-section from 6.6 to 8.1×10−21 cm2 and slightly decreasing emission lifetime from 3.4 to 3.1 ms compared to pure oxide glass.

Preparation and spectral characterization of new Er3+-doped TeO2–B2O3–WO3–ZnO–ZnS glasses

Erbium-doped TeO2-based oxysulfide glasses have been prepared in argon atmosphere in graphite crucibles. The results of thermal analysis and spectroscopic properties of Er3+ have been studied in terms of sulfide influence. As a function of composition, we have measured principally the optical absorption, spontaneous emission and lifetime of the materials. Judd–Ofelt theory was introduced to calculate bandwidth and emission cross-section of Er3+. The results demonstrate that addition of sulfide in tellurite glasses results in broad emission spectra, with high emission cross-section, slightly low emission lifetime and a comparatively high thermal stability as pure oxide glasses.