Efficient blue upconversion emission in Tm3+ via energy transfer from Yb3+ doped in lithium modified tellurite glass

Abstract

Intense blue and red upconversion emissions were obtained in Tm3+ doped tellurite glass when codoped with Yb3+ ions on pumping with 798nm radiation. The highest intensity of the blue emission was found for glasses with 0.5mol% Tm3+ and 6.0mol% Yb3+. From a study of the dependence of the upconversion intensity on excitation intensity, it is concluded that emissions are due to Tm3+ ions and involve cooperative energy transfer as well as energy transfer from Yb3+ to Tm3+ ions. Lifetime of the Tm3+ level, which is responsible for the intense blue emission, has been measured for various concentrations of Yb3+.