Composition dependence visible fluorescence from praseodymium ions doped Al2O3–CaO-M(M=B2O3, GeO2, Ga2O3) glasses

Abstract

Pr3+ doped Al2O3–CaO based glasses were excellent candidate optical gain mediums for visible solid-state lasers due to its wide transmittance region and excellent mechanical properties. However, poor glass-forming ability limited its further application in visible fiber laser. In this work, B2O3, GeO2, Ga2O3 were employed for modifying the glass-forming ability and lowing the melting temperature of the Al2O3–CaO based glasses. By introducing 15 mol% GeO2 and Ga2O3, the thermal stability ΔT were enlarged to be 199 and 264 °C, respectively. The influence of glass composition on the fluorescence characteristic of Pr3+ were systematically investigated. For lower doping concentration, different multiphonon relaxation rare of 3P0 and 1D2 energy levels accounting for the different fluorescence spectra of Pr3+ doped Al–Ga, Al–Ge and Al–B glasses, while for the higher doping concentration, cross relaxation processes lead to the fluorescence was gradually dominated by the transition of 3P0 with increasing Pr3+ concentration.