Abstract

Variable frequency ellipsometry provides a measure of the linear, and the second-and third-order nonlinear optical properties, simultaneously, in low glass transition temperature photorefractive polymer composites. This class of photorefractive materials has recently demonstrated near 100% four-wave mixing diffraction efficiency and high net optical gain,^1,2 and has demonstrated proof-of-principle applications in holographic data storage, dynamic holographic interferometry, and optical correlators. The high diffraction efficiencies in these materials is due not only to the quadratic and cubic electro-optic effects, but also to a contribution to the refractive index modulation by the linear poling birefringence. Using the variable-frequency ellipsometric technique, we measure the total refractive index modulation as a function of the frequency of the appEed electric field. Prom these measurements we deduce the relative contributions of the poling birefringence, the Pockels, and the Kerr effects. By applying the oriented gas model we determine the microscopic properties of the nonlinear optical chromophore, including the anisotropic polarizability, and the first and second hyperpolarizabilities.

© 1996 Optical Society of America