The effect of Tb3+on magneto-optical properties of GeO2-B2O3-Li2O-MgO glasses

In this work, the paramagnetic magneto-optical glasses with composition of GeO2-B2O3-Li2O-MgO (GBLM) doped with 20-40 mol%Tb3+ ions were prepared by the high temperature melting method, and the influence of different concentrations of Tb3+ ions on the structure, luminescence and magneto-optical properties of the GBLM glass were investigated. It is found that when the doping concentration of Tb2O3 is 40 mol%, the density and effective doping concentration of Tb3+ ion of the GBLM glass are 5.87 g/cm3 and 13.58 x 1021 /cm3. Importantly, GBLM glasses exhibit good magneto-optical properties. When the wavelength of incident light is 633 nm, the Verdet constant of GBLM magneto-optical glass doped with 40 mol%Tb2O3 can reach -158.56 rad/(T center dot m), -143.04 rad/(T center dot m) at 273.15 K and 298.15 K, respectively, which are better than that of Terbium Gallium Garnet Crystal (TGG, -134 rad/(T center dot m)). Additionally, due to the 5D4-*7F5 energy level transition of Tb3+, GBLM glass has bright green light emission near 544 nm. All these results indicate that there are broad application prospect for GBLM magneto-optical glass in optical isolators.