Optical spectroscopy and crystal-field strength of Cr3+ in various solid matrixes

The Cr3+:BeAl2O4 crystal, Cr3:LiNbO3 crystal, and ZnO-Al2O3-SiO2 glass-ceramic were obtained by the Czochralski technique, Bridgman method, and melting processing, respectively. The optical absorption and emission spectra of the above Cr3-incorporated solid-state materials were recorded. The technical parameters for growing high-quality Cr3+:BeAl2O4 and Cr3+:LINbO3 crystals were obtained. The results indicate that the optical absorption and fluorescence spectra of Cr3+ show quite a few differences in various matrixes. The sharp line emissions were observed in the Cr3+:BeAl2O4 and Cr3+:LiNbO3 crystals. The crystal-field parameters (Dq) for Cr3+ in different matrixes were calculated from their corresponding spectra. It is indicated that Cr3+:BeAl2O4 and Cr3+:LiNbO3 belong to the high-field site crystal, while the Cr3+:ZnO-Al2O3-SiO2 glass and glass-ceramic belong to the weak-field site crystal.