Comparative study of the luminescence of Al2O3:Ti and Al2O3 crystals under VUV synchrotron radiation excitation

► Comparison of the luminescence properties of Al2O3:Ti and Al2O3 crystals. ► Interaction between Ti ions and intrinsic defects of Al2O3 host. ► Formation of excitons localized around Ti ions. The comparative study of the luminescent properties of Al2O3:Ti crystal in comparison with those for undoped Al2O3 crystal counterpart is performed under synchrotron radiation excitation with an energy of 3.7–25eV. Apart from the main emission band peaked at 725nm related to the 2E→2T2 radiative transitions of Ti3+ ions, the luminescence of excitons localized around Ti ions in the band peaked at 290nm and the luminescence of F+–Ti and F–Ti centers in the bands peaked at 325 and 434nm are also found in the emission spectra of Al2O3:Ti crystal. We show also that the luminescence of Ti3+ ions in Al2O3:Ti crystal can be effectively excited by the luminescence of excitons localized around Ti dopant as well as by the luminescence of F–Ti centers.