Ellipsometric measurements of poling birefringence, the pockels effect, and the kerr effect in high-performance photorefractive polymer composites

Using a simple ellipsometric technique, we measure the total refractive-index modulation as a function of the frequency of the applied electric field in low glass-transition-temperature photorefractive polymer composites. From these measurements we deduce the relative contributions of the poling birefringence and the Pockels and 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 the second hyperpolarizabilities. In the search for new high-performance materials, the technique provides a measure of the linear and the second- and third-order nonlinear optical properties simultaneously.