Strong emission at 1000 nm from Pr3+/Yb3+-codoped multicomponent tellurite glass

Abstract

Abstract We have investigated the spectroscopic properties of Pr3+-doped and Pr3+/Yb3+-codoped tellurite glass with the molar composition 78TeO2–10Nb2O5–5PbO–1PbF2–5Li2O–1La2O3. Analysis of the absorption data has allowed us to calculate the radiative lifetimes of 3P0 excited state of Pr3+ ions and 2F5/2 excited state of Yb3+ ions as being equal to 9.43 and 440 µs, respectively. These values appear to be much higher than those obtained from the lifetime measurements indicating the presence of various energy transfer mechanisms. This conclusion is supported by analysis of the emission spectra obtained for doped glasses under the 445 nm excitation; the visible spectra consist of only Pr3+ transitions, while the near infrared spectrum of Pr3+/Yb3+-codoped glass demonstrates a strong emission from the 2F5/2 excited state of Yb3+ ion around 1000 nm. This emission is a result of the Pr3+–Yb3+ down-conversion energy transfer and its efficiency for our Pr3+/Yb3+-codoped glass is estimated as 29%. For potential applications, it is important to increase this efficiency and further studies are desirable, in particular, an optimal choice of Pr3+ and Yb3+ concentrations to minimize non-radiative energy transfers among the ions through cross-relaxation and energy migration processes.