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

Abstract We have investigated the spectroscopic properties of Pr 3+ -doped and Pr 3+ /Yb 3+ -codoped tellurite glass with the molar composition 78TeO 2 –10Nb 2 O 5 –5PbO–1PbF 2 –5Li 2 O–1La 2 O 3 . Analysis of the absorption data has allowed us to calculate the radiative lifetimes of 3 P 0 excited state of Pr 3+ ions and 2 F 5/2 excited state of Yb 3+ 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 Pr 3+ transitions, while the near infrared spectrum of Pr 3+ /Yb 3+ -codoped glass demonstrates a strong emission from the 2 F 5/2 excited state of Yb 3+ ion around 1000 nm. This emission is a result of the Pr 3+ –Yb 3+ down-conversion energy transfer and its efficiency for our Pr 3+ /Yb 3+ -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 Pr 3+ and Yb 3+ concentrations to minimize non-radiative energy transfers among the ions through cross-relaxation and energy migration processes.