High photorefractive sensitivity in an n-type 45-deg-cut BaTiO3 crystal

The beam-coupling properties of a cobalt-doped oxygen-reduced n-type barium titanate crystal are reported in the 0 deg and 45 deg crystallographic orientations. Oxygen reduction improved the response time of the 0-deg-cut crystal by a factor of about 4.5 without diminishing the beam-coupling gain. The 45-deg-cut crystal has a peak gain of about 38.7/cm, a response time of about 21 ms, and a photorefractive sensitivity of 3.44 cu cm/kJ. From response time measurements an equivalent percentage change in the dc dielectric constant and the mobility with respect to crystallographic orientation is inferred.