The spectral characteristics of the photorefractive effect in barium-strontium Niobate crystals

Abstract
The photorefractive effect in ferroelectric crystals is well known to be due to the formation of a local internal field which gives rise to the refractive index change via linear electrooptic effect.1,2 In LiNbO3 the most important role in formation of the internal field has been shown to be played by the bulk photovoltaic effect.3,4 However such mechanism appears is not the only one possible. In other cases the internal field is supposed to originate in screening.1,5