Enhanced 2 μm fluorescence and thermal stability in Ho3+/Tm3+ codoped WO3 modified tellurite glasses

A certain amount of WO3 oxide was introduced into the Ho3+/Tm3+ codoped tellurite glass, and the absorption spectra, fluorescence spectra, Raman spectra, X-ray diffraction patterns and differential scanning calorimeter curves were measured to illustrate the enhanced effects of WO3 on the 2 mu m fluorescence of Ho3+ and thermal stability of glass host. Under the excitation of 808 nm LD, the 2 mu m fluorescence of Ho3+ increases obviously with the partial substitution of TeO2 by WO3 oxide, which is attributed to the enhanced energy transfer process from Tm3+:F-3(4) to Ho3+:I-5(7) level by providing a relatively large phonon energy. Meanwhile, the thermal stability of glass host increases accordingly, which is mainly attributed to the formation of thermal stability W=O bond. The intense 2 mu m fluorescence together with good thermal stability indicates that Ho3+/Tm3+ codoped WO3 modified tellurite glass is a potential laser glass for efficient 2 mu m emission. (C) 2014 Elsevier B.V. All rights reserved.