Accuracy of the Judd-Ofelt theory

The accuracy of the Judd-Ofelt theory is investigated in several rare earth doped glasses. Using a normalized method to fit the experimental data, we show that an average accuracy of 5 to 15% is often obtained. However, large errors (up to 35%) can be found on some transitions, even in the case of ions usually considered as well described by the theory. These errors tend also to depend strongly on the materials so that prediction of the accuracy of a calculated intensity is difficult. The Judd-Ofelt parameters found with the normalized method may also differ from those computed in the usual way. Moreover, even in relatively close compositions, quality of the fits can largely vary, weakening possible correlations between compositions and Judd-Ofelt parameters.