Self-defocusing, self-focusing, and speckle in LiNbO(3) and LiNbO(3):Fe crystals.

The characteristics of light-induced scattering in LiNbO(3) and LiNbO(3):Fe crystals are studied. The experimental and theoretical results show that the light-induced scattering for an extraordinary illumination beam consists of self-defocusing, self-focusing, and speckle. They are caused by the light-induced lensing and fluctuation of the refractive index in the crystals.