GROWTH AND CHARACTERIZATION OF BI12(SI1-XTIX)O20 MIXED-CRYSTALS

Crystal growth of a sillenite structure with a composition of Bi12(Si1 -xTix)O20 and the corresponding optical characteristics have been syst ematically examined. The incongruent melting materials Bi12TiO20(BTO) have been observed to form a solid solution with congruent melting mat erials Bi12SiO20(BSO) for the whole range of the x value. The cutoff w avelength increases and the optical activity decreases linearly with B TO content in the crystals. The photorefractive effect is modified sig nificantly due to the addition of BTO. The diffraction efficiency (eta ) of the photorefractive grating increases first with BTO content for x less-than-or-equal-to 0.33 and saturates for a larger amount of BTO addition. The response speed is, however, promoted markedly for x grea ter-than-or-equal-to 0.48.