V. V. Shemet

YAG and Y2O3 laser ceramics from nonagglomerated nanopowders

Undoped and Nd- or Yb-doped laser-grade yttrium aluminum garnet and (Y,La)2O3 ceramics with a transmittance above 80% in the 1-μm lasing region have been prepared by solid-state reactions using nonagglomerated Y2O3 and Al2O3 nanopowders. The Y2O3 nanopowders were prepared via laser evaporation, chemical precipitation from urea solutions, and grinding of commercially available Y2O3 in a purposedesigned laboratory-scale attritor at stirrer rotation rates of up to 1500 rpm. The YAG ceramics were prepared using commercially available Al2O3. After grinding, all of the powders had a particle size on the order of a hundred nanometers. Green compacts produced from the nanopowders were sintered in a vacuum furnace between 1615 and 1750°C to give highly transparent ceramic samples.

Superlattice ZnSxSe1−x/ZnSySe1−y on (100) GaAs obtained by a photoassistant metal-organic chemical vapour deposition method

Abstract The influence of radiation in the visible spectral range on the growth rate and composition of ZnSxSe1−x during the usual metal-organic chemical vapour deposition process was observed. This fact was used to grow the superlattice under pulse radiation from a xenon or tungsten lamp directed at a GaAs substrate. Superlattices with periods of 60–1500 A were obtained by this method.

Laser-quality oxide Y3Al5O12 ceramics. Comparative studies of its basic characteristics and laser ceramics of a known manufacturer

The effect of sintering aids of SiO2, ZrO2, B2O3, and MgO oxides on the optimum sintering temperature, ceramics grain growth, total volume of residual pores, and optical quality of obtained ceramics is studied. The best combinations of sintering aids are found; as a result, YAG:Nd (1 at%) samples of ceramics of high optical quality are obtained. An original method for characterizing laser properties of ceramics is developed. Comparative measurements of main laser characteristics of the obtained ceramics and ceramics of the Konoshima Chemical Corp. Ltd wellknown in the world practice, are performed.