Optical loss and Nd3+ non-radiative relaxation by Cu, Fe and several rare earth impurities in phosphate laser glasses

Extinction coefficients (at 1053 nm) and Nd3+ fluorescence quenching rates are reported for Cu, Fe, Dy, Pr, Sm and Ce at doping concentrations up to 1000 ppmw in two meta-phosphate laser glasses melted under oxidizing conditions (1 atmosphere O2). The extinction coefficient and quenching rate for Cu are 2.7(±0.1)×10−3 cm−1/ppmw and 10.4±0.2 Hz/ppmw, respectively. The extinction coefficient and quenching rate for Fe are concentration dependent below 300 ppmw due to an observed change in Fe2+/Fe3+ distribution; an empirically derived expression is used to describe this effect. The extinction coefficient and quenching rates for Dy, Pr and Sm, are nearly the same: 1.6, 1.2 and 1.3(±0.05)×10−5 cm−1/ppmw and 0.89, 0.72 and 0.63±0.04 Hz/ppmw, respectively, while those for Ce are less: 0.84(±0.03)×10−5 cm−1/ppmw and 0.061±0.03 Hz/ppmw. The quenching results are explained using the Förster–Dexter theory for dipolar energy transfer.