Avoiding hologram bending in photorefractive crystals

Dynamic coupled-wave theory predicts the bending of recorded hologram phase planes in most photorefractive crystals. Bent holograms occur in LiNbO(3) and other photovoltaic crystals that are particularly interesting as holographic storage media and result in a reduced overall diffraction eff iciency. We show that hologram bending in LiNbO(3) can be avoided or at least sensibly reduced by use of an actively stabilized recording technique.