Photorefractive effects in periodically poled ferroelectrics

A quantitative analysis of the steady-state photorefractive index perturbations caused by a given optical irradiance distribution in a periodically poled ferroelectric is presented. Axially invariant index perturbations that are due to the photogalvanic effect are reduced compared with those in a homogeneously poled crystal by approximately the square of the product of the poling-grating wave vector (K(g)) and a characteristic transverse dimension of the irradiance. This result is consistent with empirical observations in periodically poled LiNbO(3) of much higher resistance to photorefractive damage.