Investigation of oxide and fluoride hosts for blue-green lasers

Mixed crystals of the perovskite type structure of the system La A1(1-x) Sc(x) O3 were examined over the compositions of x=0.15-0.30. Single crystals were grown from melts in iridium crucibles using the Czochralski method. Seed crystals of (111) pure La A1 O3 were used. The growth atmosphere was controlled at 99.75% N2 and 0.25% H2. Dopants of Ce(3+) were maintained at 0.01-0.05 atomic per cent. Preliminary work on polycrystalline materials showed that blue-green luminescence at 485 nm was found. The grown crystals had various amounts of Sc incorporated and were usually translucent. At the x=.30 formulation of melt, about 60-75% of Sc is believed to enter the crystal. No direct evidence was found for ordered type structures. The phase data, compositions, crystal quality, luminescence data, and x-ray results are discussed. Several mixed fluorides were examined for possible blue-green emission by doping with rare earths. Among the host compositions was K Mg Y3 F12, a crystal which could be doped with transition elements and rare earths. A sizeable effort provided fairly good single crystal s for future seeds. Several polycrystalline preparations were made with Ce(3+), Pr(3+), Ti(3+), Nd(3+), Cr(3+), and Er(3+).