Near-infrared downconversion in Pr3+/Yb3+ co-doped boro-aluminosilicate glasses and LaBO3 glass ceramics

We report on downconversion of one blue photon to two near-infrared (NIR) photons (similar to 10000 cm(-1)) in Pr3+/Yb3+ co-doped SrO-La2O3-Al2O3-B2O3-SiO2 glasses and LaBO3 glass ceramics. The Pr3+ ions act as broadband spectral sensitizer in the spectral range of 415-505 nm. Energy transfer occurs subsequently from Pr3+ to Yb3+, followed by re-emission in the NIR spectral range. The transfer efficiency is indicated by the degree of decrease of Pr3+-related photoluminescence (PL) and PL lifetime of the P-3(0) and D-1(2) levels with increasing Yb3+ concentration. For the present case, we find an optimum dopant concentration of Yb2O3 of similar to 0.5 mol % for a Pr2O3 concentration of 1.0 mol %. A theoretical maximum of quantum efficiency of 183% is reached for 5 mol % of Yb2O3. PL characteristics (absorption cross section and emission lifetime) are further improved upon precipitation of crystalline LaBO3, where both Pr3+ and Yb3+ ions occupy La3+ sites with an assumedly statistical distribution and a high degree of partitioning. (C) 2013 Optical Society of America