The d-d luminescence of Ti3+ ions was first observed in the double Ti/SiO2
system at room temperature. Silica glass doped with titanium was synthesise
d in a steady-state laser plume. The luminescent state was obtained by prod
ucing oxygen-deficient centres in the chemical reaction between Ti and SiO2
. Comparison of the luminescence and absorption spectra of the titanium-dop
ed silica glass with the spectra of a Ti3+:Al2O3 crystal suggests that the
690-nm luminescence band belongs to Ti3+ ions.