Optical second-harmonic scattering from a non-diffusive random distribution of nonlinear domains

We show that the weak second harmonic light generated from a random distribution of nonlinear domains of transparent Strontium Barium Niobáte crystals can display a particularly intense generation in the forward direction. By using a theoretical model able to analyze the optical response of arbitrary distributions of three-dimensional nonlinear volumes of any shape, we found that the physical origin of this observation can be explained in terms of the scattering of light by a single nonlinear domain.