One kind of new Ti3+ luminous center in Ti:Al2O3 crystals

Abstract In the optical absorption spectra of Ti:Al2O3 crystal doped with higher concentration of titanium and annealed with hydrogen, in addition to the main absorption band of T i A l 3 + (490 nm, 540 nm), a small absorption band of 390 nm and a concomitant small bump on the short-wave side of the 490 nm absorption band was often observed. In this study, an independent optical absorption center that also has doublet structured optical absorption bands at 388 and 460 nm was separated from the above spectra by means of spectral decomposition, and its polarization property and annealing effect are consistent with the main absorption band of T i A l 3 + . It was supposed to be another kind of Ti3+ center related to interstitial Ti3+ locating at the intrinsic vacant octahedral in the corundum structure. Moreover, this Ti3+ center also produced a wide emission band centered at 760 nm, with weaker intensity, which indicated that there were two kinds of Ti3+ luminous centers in Ti:Al2O3 crystal: one is T i A l 3 + in the lattice site of A1, the other is T i i 3 + in the interstitial site.