Matrix effect on local structure surrounding Yb³⁺and spontaneous emission probability in oxide glasses

Extended X-ray absorption fine structure measurements have been performed on Yb3+ in silicate, borate, phosphate, and gallate glasses in order to investigate the local structures surrounding Yb3+. The local structures of Yb3+ ions in silicate, borate, and phosphate glasses were similar to those of Er3+ ions. Yb3+ ions do not occupy the network structural sites, but sit around the terminal region of the network or the region between the networks in these glasses. On the other hand, Yb3+ ions substitute the Ga3+ sites in complex anion structural units of the K2O-Ga2O3-Nb2O5 glasses. We classified the local structures surrounding Yb3+ ions in oxide glasses into two types: the former and the latter are interstitial and substitutive types, respectively. The relationship between the spontaneous emission probability for 2F5/2 – 2F7/2 transition of Yb3+ and the local structure of Yb3+ in oxide glasses are discussed in terms of these two types.