Optical studies of Czochralski and hydrothermal bismuth silicate

Abstract

Bismuth silicate in the sillenite structure, (Bi 12SiO 20), is a photorefractive material of interest for applications in two-wave and four-wave mixing, optical correlation and holographic storage devices. It has higher sensitivity and speed than other visible light photorefractive materials. Currently available material is obtained by the Czochralski growth process or the directional gradient freeze technique. These methods procedure material of adequate quality for most purposes but problems with crystal uniformity and reproductibility limit the material for some applications. The hydrothermal growth technique will potentially yield highly reproducible material of large size and excellent uniformity. Doping studies on both Czochralski and hydrothermal crystal indicate that the photorefractive properties may be tailored to individual applications.