Abstract

With the ever increasing importance of semiconductor lasers which operate in the near infrared, the greater the desire for nonlinear optical devices such as phase conjugate mirrors which will function at these wavelengths. Until recently almost all devices utilizing photorefractive crystals were demonstrated using visible light only. However, since these very same crystals are also photorefractive in the 0.8-1.1-μm wavelength region,¹ many of the currently known devices should also operate at these longer wavelengths. With this motivation in mind, we have proceeded to study the photorefractive properties of ferroelectric crystals such as BaTiO₃, SBN:60, SBN:Ce, SBN;75, and BSKNN in the near-infrared region utilizing argon, dye, semiconductor, and YAG lasers. Specifically, we measured absorption coefficients, response times, and two-beam coupling coefficients throughout this new wavelength region and we have found significant photorefractive response in all the crystals studied. For example, we routinely measured coupling coefficients >1 cm⁻¹ in many of the crystals with response times at 1 W/cm² in the 0.1–10-s regime depending on the crystal and wavelength used. Throughout this wavelength range negligible absorption was detected. Finally, several theoretical models were proposed and developed to describe the broad wavelength response in these crystals.

© 1986 Optical Society of America