Optical characterization of Tm3+-doped KGd(WO4)2 single crystals

Abstract In this paper we present the optical characterization of KGd(WO4)2 single crystals doped with thulium ions at several concentrations from 0.1% to 10% grown by the top-seeded-solution-growth slow-cooling method. Polarized optical absorption was carried out between 350 nm (28,571 cm−1) and 2 μm (5000 cm−1), at room temperature (RT) and low temperature (6 K). We determined the splitting of the corresponding excited energy levels of thulium in KGd(WO4)2. Luminescence spectra was obtained between 300 nm (33,333 cm−1) and 2.5 μm (4000 cm−1) by pumping at 688 nm (14,535 cm−1) and 788 nm (12,690 cm−1) from 10 K to RT. Finally, we proposed a 788 nm pumping scheme for the generation of the emissions.