[Spectroscopic characterization of Tm3+ ions in zinc tungstate crystals]

A series of high quality ZnWO4:Tm3+ single crystals were grown with Czochralski method. The concentrations of thulium ions were 0.1, 0.3, 0.5, 0.7 and 1.0 mol%, respectively. When ZnWO4:Tm3+ single crystals were excited by 807 nm laser, the up-conversion luminescence peaks at 486 and 695 nm which corresponded to transitions 1G4-->3H6 and 3F3-->3 H6, respectively, were detected. The intensity of 695 nm luminescence varied with the pump power in a double logarithmic relation whose indexes were 0.8 and 1.1 orders, respectively.