Luminescence spectroscopy of the Gd-rich Ce3+-, Tb3+- and Mn2+-doped phosphate glasses

Absorption, emission and excitation spectra and luminescence decay kinetics of Na(K)GdCe, NaGdTb and NaGdMn phosphate glasses and their dependence on the temperature (in the 1.7-300 K range) and on the glass composition have been studied. The processes of energy migration through the Gd3+ ions and following energy transfer in Gd3+-impurity pairs have been compared for the three types of the glasses studied. It has been suggested that the Gd3+ --> Tb3+ energy transfer occurs only in the closest pairs through a very short-range exchange interaction, while the Gd3+ --> Ce3+ and Gd3+ --> Mn2+ energy transfer is possible also in more separated pairs mainly due to the longer-range multipolar Gd3+-impurity interaction.