Abstract

In 1984 Ducharme and Feinberg¹ showed that the speed of the photorefractive effect in barium titanate was not a linear function of the light intensity I, but varied instead as I^x, with x < 1. This sublinear dependence prevailed over four orders of the light intensity ( 0.01 Watt/cm² <I < 100 Watt/cm² ). They also showed that the power x increased with increasing temperature. In 1988, Mahgerefteh and Feinberg² showed that the speed of the photorefractive effect in barium titanate obeyed the same I^x power law for the case of pulsed illumination as well as for cw illumination, even though the peak intensities used in the pulsed case were 10⁴ times that of the cw experiments. This result suggested that the I^x power law was valid for a range spanning eight orders of magnitude in the light intensity.

© 1990 Optical Society of America