Judd-Ofelt Analysis and Emission Properties of Dy Ions in Borogermanate Glasses.

Borogermanate glasses singly doped with Dy ions were synthesized and then studied using the absorption and luminescence spectra. Spectroscopic changes of Dy ions have been examined for compositional-dependent glasses with various molar ratios GeO:BO. In this work, several spectroscopic parameters of Dy ions were obtained experimentally and compared to the calculated values from the Judd-Ofelt theory. Luminescence spectra measured for borogermanate glasses consist of blue, yellow and red bands, which correspond to F → H, F → H and F → H transitions of Dy, respectively. Luminescence lifetimes for the F excited state are reduced, whereas the stimulated emission cross-sections for the most intense F → H yellow transition of Dy increase with increasing GeO and decreasing BO concentrations in glass-hosts. Quantum efficiency of the F (Dy) excited state is nearly independent on molar ratios GeO:BO. Attractive spectroscopic properties related to the F → H transition of Dy ions are found for borogermanate glasses implying their potential utility for yellow laser action and solid-state lighting technology.