Abstract

Because of their large optical nonlinearities, photorefractive materials are candidates for use in optical devices. Typically, gains of a few thousand are achieved (e.g., in image amplification) with intensity two-beam-coupling coefficients in the range of ~10-20-cm^-1.1,2 In this paper, we demonstrate two-beam-coupling coefficients as high as Γ = 65 cm^-1 for extraordinary polarized light in a wedged crystal of BaTiO₃ at a near-optimal grating spacing and orientation. This coupling coefficient for extraordinary polarization is, to our knowledge, by far the largest measured to date in any bulk photorefractive sample, and it causes the intensity of a beam to double after traversing only 100 μm of the crystal.

© 1990 Optical Society of America