Abstract

Photorefractive materials, for instance photorefractive crystals and photorefractive ceramics to which our main interest is dedicated, are of importance for optical storage applications. The dynamic-holographic recording process as well as the process of reading out a stored hologram, however, may be strongly disturbed by a simultaneous increase of scattered radiation. This “holographic scattering” has first been observed as early as 1971 by Amodei and Stäbler [1] in LiNbO₃. In LiNbO₃ it has further been investigated in references [2] to [9], in LiTaO₃ in references [6, 10], in (Sr_x:Ba_1−x)_1−y/(Nb₂O₆)_y in references [11, 12], and in BaTiO₃ in references [6, 7, 13, 14, 15, 16, 17]. The effect is believed to result from random gratings written by the beams illuminating the material and by light scattered from inhomogeneities of the material [3]. As a transient effect, amplification of the scattered radiation is typical. For the stationary state, however, amplification or decrease of the scattered radiation is possible [18]. The whole process is an exciting but complicated example of dynamical holography [19].

© 1987 Optical Society of America