Four-Wave Interaction Phenomena In Holographic Scattering

We present experimental evidence that reflection at the crystal back face due to the large refractive indices of LiNbO3 and LiTaO3 is responsible for strong holographic scattering effects. By these means four-wave interaction phenomena occur. The light is isotropically scattered (equal polarization of incident and scattered wave) in a cone emerging in forward and backward direction from the sample with a cone angle equal to the angle of reflection. We explain the geometry of the patterns produced by the incident reflected and scattered beams and investigate the angular and time dependence of the scattered light.