Evidence of two Yb3+ crystallographic sites occupancy in Y3Al5O12 ceramics from an in depth spectroscopic analysis

In this paper a complete spectroscopic analysis of low-temperature absorption and emission spectra of 10 at.% Yb:YAG ceramic are investigated. On the basis of the analysis of the temperature dependences of individual spectral lines (from 10 K to 300 K), as well of the joint analysis of the Raman spectra and the temperature-resolved absorption and emission spectra a two center model of Yb3þ doping ion is proposed. Namely, most of the ytterbium ions replace yttrium ions in dodecahedral positions (c-site), while a small part replaces yttrium ions in octahedral positions (a-anti-site).