Effect of Network Modifier on Spontaneous Emission Probabilities of Er 3+ in Oxide Glasses

Compositional dependence of spontaneous emission probabilities of Er 3+ was studied for silicate, borate, and phosphate glasses using the Judd–Ofelt theory. Through all of the glass systems, spontaneous emission probabilities of the 4 I 13/2 → 4 I 15/29 → 4 I 9/2 → 4 I J , and 4 S 3/2 → 4 I J ( J = 9/2, 11/2,13/2,15/2) transitions increased with increased ionic packing ratio of the glass host, which varied markedly with the type of network modifier. The effect of Er–O covalency on the transition probabilities was discussed from the spectral profile of the 4 I 15/2 → 4 I 3/2 transition in terms of nephelauxetic effect.