Luminescent Properties of Yb-Sensitized AlF3-Based Glasses

Abstract

Rare earth ions can easily be incorporated into fluoride glasses in moderate to large concentrations, and, due to their low phonon energy, these glasses appear to have many advantages over oxide glasses as hosts for rare earth ions used in optical amplifiers and lasers. We have therefore investigated the luminescence and radiative lifetimes of Pr3+, Pr3+/Yb3+ and Pr3+/Yb3+/Lu3+ doped bulk AlF3-based glass samples as a function of rare earth ion concentration. Initial results show a lifetime of about 150 µs for the 1G4 → 3H4 state and a 20% decrease with the addition of Yb3+. In addition we find that the addition of 2 wt% of Yb increases the fluorescence of Pr3+ at 1.32 microns by a factor of 7 when excited with 488 nm radiation. The effect of Yb3+ and Lu3+ on the 1G4 → 3H5, 1D2 → 3F4 and 1D2 → 1G4 transitions of praseodymium would be presented.