OPTICAL-PROPERTIES OF SODIUM BETA-ALUMINA SINGLE-CRYSTALS DOPED WITH NEODYMIUM AND CHROMIUM-NEODYMIUM

Single crystals of sodium p-alumina have been grown by two methods: fl ux evaporation and a new process, solid-vapour reaction. These compoun ds were doped with neodymium through a homogeneous ion-exchange reacti on. Their X-ray diffuse scattering patterns show a two-dimensional (2D ) superstructure (a root 3; a root 3) for Nd beta-alumina. The optical behaviour of NaNd beta-alumina single crystals is reported here. A st rong absorption occurs at 580 nm. Nd3+ emission shows a broad band (FW HM about 30 nm) centred at 1.06 mu m and the Nd3+ lifetime measured at room temperature is about 530 mu s. Finally, chromium-neodymium co-do ped samples of beta-alumina single crystals are investigated. Time-res olved spectroscopy and lifetime analysis indicate that Cr-->Nd energy transfer takes place in this host matrix.