Influence of annealing conditions on the optical properties of chromium-doped ceramic Y3Al5O12

Transparent chromium-doped Y3Al5O12 ceramics were fabricated. The absorption and emission spectra of these ceramics were measured at room temperature. The absorption and emission spectra of Cr:Y3Al5O12 ceramics varied with annealing conditions. By high-temperature annealing, the absorption intensity increased, and its peak wavelengths changed from 430 nm and 600 nm to approximately 465 nm and 612 nm, respectively, because the valence changed from Cr3+ to Cr4+. For the samples, emissions from both Cr3+ and Cr4+ ions were detected. However, emission from only the Cr3+ ions was observed in samples that annealed at low temperature or unannealed.