Abstract
The fluorescence of rare-earth ions RE3+ = Pr3+, Er3+ and Tm3+ has been compared in the transition-metal fluoride glass (36 mol% PbF2–24 mol% ZnF2–35 mol% GaF3–5 mol% YF3–2Al mol% F3) doped with either REF3 or RECl3. For the phonon-sensitive radiative transition, the lifetime is prolonged at low RECl3 concentrations because the phonon energy and/or electron coupling are reduced. For Pr3+, the doping with PrCl3 increases the lifetime by 50% with respect to PrF3 doping. These results suggest that the Cl− ions remain in the coordination sphere of the RE3+ ions in the ReCl3-doped glass after melting.
Acknowledgements
This research was supported by the French Réseau National de Recherche en Télécommunication under grant 00S0508/13, Fondo per gli Investimenti della Ricerca di Base (FIRB) ‘Nanotecnologie, microtecnologie, sviluppo integrato di materiali’ and Ministero dell’istruzione dell’Università e della Ricerca (MIUR) (Cofinanziamento progretti di ricerca di Interesse Nazionale (COFIN) 2002) ‘Materiali nanostrutturati per l’ottica integrata’ Italian projects.