Spectroscopic studies on Yb3+-doped tungsten-tellurite glasses for laser applications

Tungsten tellurite glasses (TeO2-WO3-ZrO2) doped with various concentrations of Yb3+ ions have been prepared by the conventional melt-quenching method and systematically studied their spectroscopic and laser properties. The spectroscopic properties and some of the laser parameters have been evaluated from the measured absorption and emission spectra. Emission cross-sections evaluated from the McCumber and the Fuchtbauer-Ladenburg methods are found to be in good agreement. The absorption and emission cross-sections are found to be in the range of 2.78-1.30 (x 10(-20) cm(2)) and 3.64-1.83 (x 10(-20) cm(2)), respectively, when Yb3+ ions concentration increases from 0.01 to 3.0 mol%. A significant change in luminescence spectral profile for higher concentration (> 0.1 mol%) of Yb3+ ions has been explained as due to reabsorption effects. An initial increase of lifetime for the F-2(5/2) level up to 0.5 mol% and decrease thereafter for higher concentrations (> 0.5 mol%) of Yb3+ ions has been explained with a suitable mechanism. The results of spectroscopic and laser parameters indicate that tungsten-tellurite glasses have potential applications as gain media for lasers and optical amplifiers.