TEMPERATURE-DEPENDENT CONCENTRATION QUENCHING AND SITE-DEPENDENT EFFECTS OF ND3+ FLUORESCENCE IN FLUOROPHOSPHATE GLASSES

The optical properties and temperature-dependent concentration quenchi ng of Nd3+ fluorescence have been investigated in fluorophosphate glas ses with different fluorine to oxygen ratios by using steady-state and time-resolved laser spectroscopy. Judd-Ofelt parameters were derived from the absorption spectra and used to calculate the F-4(3/2) --> I-4 (11/2) stimulated emission cross section and the F-4(3/2) radiative li fetime. For the samples doped with 1 wt % of Nd2O3 the lifetimes were found to be linear dependent on the fluorine to oxygen ratio. From the thermal behavior of lifetimes, a linear temperature dependence for th e nonradiative Nd-Nd relaxation processes has been found in the 4.2-10 0 K temperature range for samples with a molar fluorine to oxygen rati o of 6.04 doped with more than 1 wt % of Nd2O3, which is in agreement with a one-phonon-assisted process. In order to investigate the influe nce of the local coordination ions on the optical properties of rare e arths in these fluorophosphate glasses, fluorescence line-narrowing sp ectroscopy on Eu3+ has been performed. The influence of the local coor dination ions on the optical properties of Eu3+ in these fluorophospha te glasses shows the existence of a clear crossover between the behavi or of fluorinelike and oxygenlike coordination anions.