Infrared to visible upconversion luminescence properties in the system Ln2BaZnO5 (Ln = La, Gd)

We have investigated the upconversion properties of the rare-earth doped systems La2BaZnO5 (I4/mcm) and Gd2BaZnO5 (Pbnm). The dependence of the luminescence properties on the identity and the concentration of the dopants, Er3+ and Er3+ co-doped with Yb3+, as well as on the synthetic route, was examined. Following coherent excitation at 975 nm, strong upconversion emission was observed in the visible region (525, 550 and 660 nm). Power dependence studies revealed a two photon process for these emissions. In the co-doped samples, a blue emission (410 nm) could also be observed. For this emission, the power dependence studies confirmed a three photon process.