Laser-excited luminescence in Ti-doped MgAl2O4 spinel

Abstract

The photoluminescence (excitation, emission, and fluorescence decay time) spectra of spinel (Ti:MgAl2O4) excited by pulsed Nd:YAG and dye lasers have been systematically investigated. Excitation into the T2g→Eg crystal-field transition of Ti3+ produces a broad infrared emission band at 805 nm which could, in principle, be used for tunable laser applications. Two different Ti3+ centers with lifetimes of 4.2 and 41 μs contribute to this emission. At the same time this IR band can also be observed under high-intensity excitation in the ultraviolet region (266 nm) via a two-photon process.