Investigation of single-crystal silicates for blue tunable lasers. Final report, 1 September 1985-1 September 1986

The single-crystal growth of rare earth silicates was investigated for the purpose of tunable laser host. Silicates of the type R/sub 2/SiO/sub 5/, where R + La, Gd, Y were prepared from stoichiometric melts and doped with Ce/sup +3/ activator. Seed crystals were obtained from crystallized melt sections or by growth on an iridium wire. Cathodoluminescence experiments on both powders and single crystals showed wavelength shifts with different rare earth ions. The Gd, Y, and mixed crystals of Cd-Y silicates gave good bright emission with Ce/sup +3/. The emission is broadband and covers the wavelength range of 370-525nm. The peak emission can be centered near 450-460 micrometers by other compositions. Large single crystals of Gd/sub 2/SiO/sub 5/:Ce/sup +3/ were grown. One growth run of Mg/sub 2/SiO/sub 4/:Ti/sup +3/ yielded a small boule which showed cathodoluminescence under e-beam illumination.