The Photorefractive Effect In Doped Bismuth Silicon Oxide Crystals

Bismuth silicon oxide is one of the most sensitive photorefractive materials available today. It is therefore important to develop an understanding of how its photorefractive properties can be altered by adding impurities during growth. In this paper results from analyses of doped bismuth silicon oxide crystals grown by the addition of impurities to the melt during Czochralski growth are presented, and the influence of these impurities and their concentrations on the photorefractive effect are determined. Doped crystals are used in a holographic arrangement, and the effects of dopants and temperature on grating formation (erasure time and diffraction efficiency) are reported. Data on the effect of dopants on long-term retention time are also presented. The apparent effects of certain impurities on traps are reviewed. The results are discussed and compared with current models.