Thermo-optic properties of ceramic YAG at high temperatures

The thermo-optic coefficient dn/dT at 632.8 nm and thermal expansion coefficient α of transparent ceramic yttrium aluminum garnet (YAG) were measured between room temperature and 600 K. The data showed that dn/dT increases with temperature and α is in good agreement with that of single-crystal YAG. To the best of our knowledge, these are the first experimental data of the thermo-optic properties of highly transparent ceramic YAG above room temperature. We also present, using previously reported values measured below room temperature, fitting parameters for dn/dT that are valid over a wide temperature range (70–600 K) with an average error of 2.0%.