Energy transfer in Tb:Nd system and composition dependence of the J-O parameters and radiative properties of Nd3+ ions of fluorophosphate glasses

The mechanism of non-radiative energy transfer between Tb 3+ and Nd 3+ ions in fluorophosphate glass has been analyzed with the Forster-Dexter theory. Several/transfer parameters such as the transfer probability, transfer efficiency, critical transfer distance, and critical concentration have been evaluated by fitting the experimental fluorescence spectrum of those ions with that theory. The recorded emission spectrum of Tb 3+ with different Nd 3+ ion concentrations shows that the transfer process from the 5 D 4 state of Tb 3+ to the 4 G 5/2 state of Nd 3+ is driven predominantly by a dipole-dipole interaction. The effect of this energy transfer is to considerably enhance the optical gain of the 4 F 3/2 to 4 I 11/2 emission band of Nd 3+ ions. The reduction in optical gain at high activator concentrations is attributed to the concentration quenching in Nd 3+ ion pairs. In addition to this, the dependence of the J-O parameters, several radiative properties of Nd 3+ ions in the phosphate content as well as the nature of alkali content were also studied.