Intensity dependent properties of photo-induced light scattering in ferroelectric Sr_0.61Ba_0.39Nb₂O₆:Ce

Abstract

An experimental study of intensity dependent properties of photo-induced scattering (beam fanning) in Ce-doped Sr 0.61 Ba 0.39 Nb 2 O 6 , both field-free and under the action of external electric fields, is reported. A new effect, the spontaneous local reorientation of the scattering pattern, is found and is attributed to optically induced local switching of the polar structure. It is demonstrated that features of scattering observed at high intensities are governed by changes of ferroelectric and photorefractive properties of SBN in the beam area during heating up to the vicinity of the phase transition by coherent illumination.