| The recent discovery of photorefractive polymer composites with near 100% four-wave-mixing diffraction efficiency and high net optical gain by the author and coworkers at the University of Arizona has forwarded the advances of using organic materials to fabricate nonlinear optical devices. Nonlinear optical chromophores provide the optical properties for these new materials. Since there are thousands of molecules that are potential candidates to yield high performance nonlinear optical materials, a technique to quickly characterize the optical properties of these molecules is clearly needed. We have developed a frequency-dependent ellipsometric technique that simultaneously determines the first-order (anisotropic polarizability), second-order (first-hyperpolarizability), and third-order (second-hyperpolarizability) optical molecular coefficients of the chromophore. In this dissertation we will discuss the physics of these high performance nonlinear optical organic materials, and the characterization of their unique properties, leading to the development of our frequency-dependent ellipsometric technique. The technique itself will be discussed in detail, with an analysis of the molecules that are best suited for this type of measurement scheme, and a discussion of the limitations of this technique. Experimental data will be presented for a typical high performance nonlinear optical chromophore 4-(4{dollar}spprime{dollar}-nitrophenylazo)-1,3-di((3{dollar}sp{lcub}primeprime{rcub}{dollar}- or 4{dollar}sp{lcub}primeprime{rcub}{dollar}-vinyl)benzyloxy)benzene (NPADVBB). |
