Broadband second harmonic parametric scattering in ferroelectric crystals with random domains structure

We report the results of an experimental study on broadband second-harmonic (SH) parametric scattering in an un-poled strontium barium niobate (SBN) crystal with random-size ferroelectric domains. We consider different geometries of the interacting waves. The observed spatial distribution of the SHG is due to the larger facility to achieve phase matching conditions in the presence of disorder, and the polarization of the SH light can be both ordinary and extraordinary. The nonlinear coefficients of the crystal may be determined from the measurement of the SHG as a function of the fundamental beams polarization. The experimental results are in very good agreement with the predictions of our theoretical model.