Energy upconversion processes in Er3+ and Nd3+ doped RETiNbO6 crystals

Single crystals of stoichiometric lanthanide rare earth compounds, RETiNbO6, doped with Nd3+ and Er3+ ions have been grown by the laser heated pedestal growth technique. Excited state absorption resulting in energy upconverted fluorescence are observed for temperatures up to 298 K. The upconversion process is efficient because of weak nonradiative decay rate whilst energy transfer and concentration quenching processes are important in these materials. (C) 1997 Elsevier Science B.V.