Magnetic properties and photoluminescence of thulium-doped calcium aluminosilicate glasses

We report on the optical and magnetic properties of Tm2O3-doped calcium aluminosilicate glasses with dopant concentrations of up to 7 mol%. These materials provide a rare case in which high magnetic susceptibility, low Faraday rotation, Tm3+-related infrared photoluminescence and the ability to produce optical fibers are combined. From emission intensity and decay curves of the H-3(4)-> F-3(4) and (3)F4 -> H-3(6) transitions, we find cross-relaxation already for 0.5 mol% of Tm2O3 doping, indicating notable Tm2O3 clustering. This facilitates antiferromagnetic interaction and results in high magnetic susceptibility. Substitution of Al2O3 by Tm2O3 induces a more asymmetric local structural environment around Tm3+ species and enhances the diamagnetic contribution to Faraday rotation as opposed to the other rare-earth ions. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement