Crystal growth and properties of photorefractive materials BaTiO/sub 3/

Barium titanate has special features such as high beam coupling gain, self-pumped phase conjugation, high phase conjugate reflectivity, and a wide operating wavelength range. Therefore BaTiO/sub 3/ is adequate for applications to photorefractive devices with excellent electro-optic properties. The BaTiO/sub 3/ single crystals could be grown by the TSSG technique or the modified Czochralski method. The study on poling process was necessary for the optical application of grown single crystals. Furthermore the photorefractive properties were measured and compared with the data reported previously in order to characterize the quality of the grown crystals. The temperature fluctuations, the thermal gradients, and the cooling rates in the high temperature solutions were controlled during the growth process in order to improve the quality of BaTiO/sub 3/ single crystals. The BaTiO/sub 3/ crystals grown under the high thermal gradient exhibited oxygen deficiency. On the other hand, the second phases were precipitated on the BaTiO/sub 3/ crystal under the very low thermal gradient. The BaTiO/sub 3/ crystals grown under moderate thermal gradient were transparent, pale yellow and good in quality.