Abstract

Using sol–gel methods novel silica based glass ceramics containing TiO₂, Er³⁺ and Yb³⁺ ions have been prepared. Anatase and rutile crystallites composed of TiO₂, Er³⁺ and Yb³⁺ ions that segregate in the glasses have been shown to be new yellow emitting up-converting materials. It is demonstrated that by annealing SiO₂ glasses containing TiO₂, Er³⁺ and Yb³⁺ ions, crystals of either the anatase or rutile phases can be grown in the glass (dependent on annealing temperature). Laser Raman spectroscopy is shown to be a useful technique to characterise the crystallographic phases in the pure state, and in these new ceramics. Furthermore, their emission can be excited at a wavelength of 632.8 nm, and the up-converted luminescence in the visible region can be detected and monitored using a Raman spectrometer.