Abstract

Photorefractive materials have been used to demonstrate a variety of nonlinear optical applications, due to their large optical nonlinearity even with weak optical beams. To date, most photorefractive devices have used barium titanate (Ba-TiO₃) because it is commercially available and it has a large Pockels coefficient (r₄₂ = 820 × 10⁻¹² m/V). However, it is difficult to obtain single crystals of BaTiO₃ with dimensions larger than (5 mm)³. Photorefractive strontium barium niobate (SrjBat-xNbaOe or SBN) single crystals have been grown with larger dimensions (20 mm)³, and SBN also has a large Pockels coefficient (r₃₃ = 420 × 10⁻¹² m/V). Additionally, the tungsten-bronze structure of SBN has a large number of vacant lattice sites which could potentially be occupied by dopants to provide a high density of optically active impurity states. Such impurities are a prerequisite for an optically induced nonlinearity by the photorefractive effect.

© 1986 Optical Society of America