Preillumination of Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> at low temperature causes a transient enhancement of diffraction efficiency for subsequent holographic recording. Diffraction efficiencies are measured that are up to ten times larger than the stationary value. The enhancement depends on the intensity of the preillumination, on the dark delay time, and on the crystal temperature. The effect can be explained considering electron–hole competition and contributions of different levels to the charge transport.
© 1998 Optical Society of America
Xuefeng Yue, K. Buse, F. Mersch, E. Krätzig, and R. A. Rupp, "Diffraction-efficiency enhancement of photorefractive gratings in Bi4Ti3O12 at low temperatures," J. Opt. Soc. Am. B 15, 142-147 (1998)