Corporate R&D Center, Mitsui Mining and Smelting Co., Ltd., 1333-2 Haraichi, Ageo, Saitama, 362, Japan
Abstract:
Single crystals of Cr,Ca: Y3Al5O12(YAG) with different Cr and Ca concentrations were grown by the Czochralski (CZ) and floating zone (FZ) method. The analysis of absorption and emission spectra of both as-grown and oxygen-annealed crystals in relation to concentration ratio of Ca and Cr (Ca/Cr) showed that Cr4+ concentration ratio to total Cr concentration increased up to about Ca/Cr = 6, and Cr6+ can also exist. Luminescence lifetime at 1400 nm was measured as a function of Cr4+ concentration.