Rare earths in nanocrystalline glass–ceramics

Abstract

The optical spectroscopic analysis of rare earth ions in transparent oxyfluoride glass–ceramics obtained from SiO2–Al2O3–PbF2–CdF2 based precursor glasses is presented. The oscillator strengths of the optical transitions were measured from the absorption spectra of glasses and glass–ceramics doped with rare earth ions. The results were analysed in the framework of the Judd–Ofelt theory giving the values of the three Ω2, Ω4 and Ω6 intensity parameters over the rare earth series. On the other hand, high efficient infrared-to-blue upconversion has been observed in Tm3+–Yb3+ codoped glass and glass–ceramic compared to the Tm3+ single doped matrices. The contributions to the upconversion process of the rare earth ions in the nanocrystalline and in the vitreous phase of the glass–ceramics have been distinguished. Finally, laser action in Nd3+-doped glass–ceramic has been studied. Losses due to UV and visible upconverted emissions inside the laser cavity have been also estimated.