Beam fanning reversal in the ferroelectic relaxor Sr0.61Ba0.39Nb2O6 at high external electric fields

Beam fanning has been studied in the cerium-doped ferroelectric relaxor strontium–barium–niobate (Sr0.61Ba0.39Nb2O6:Ce, SBN:Ce) under the application of high external electric fields. Spatial reversal in the distribution of the scattered light is achieved both below and above the phase transition. It is shown that the photorefractive response in SBN strongly depends on the state of the polar structure of the crystal, which can be controlled by external fields. Coherent illumination of the crystal greatly facilitates the repoling process, causes a considerable refinement of the domain order in the ferroelectric phase and assists the stabilization of the polar structure in the relaxor regime. The model of scattering centers associated with refractive index anomalies located on domain walls is applied to receive detailed information about the distribution of initial seed scattering in the crystal bulk and the efficiency of nonlinear amplification of the scattering.