Self-assembly of optical patterns in lead magnesium niobate (PMN)

Abstract

Hexagonal far-field patterns are observed in the initially Gaussian laser light transmitted at low powers (<1.0 W in a 50 mm diameter) through single-crystal lead magnesium niobate (PMN). These are absent in fine-grained ceramics of the same material and are interpreted in terms of Firth's photorefractive theory of accidental holography.