Large Nonlinear Refraction and Higher Order Nonlinear Optical Effects in a Novel Organic Dendrimer

The fast electronic nonlinear optical (NLO) properties of a novel synthetic organic dendrimer are reported. The complete synthesis of the organic dendrimer is provided. Both the z-scan and self-phase modulation techniques were used to measure the nonlinear refractive index. The magnitude of the nonlinear refractive index (n₂) was measured to be 1.1 × 10^-4 cm²/GW. The presence of two-photon absorption was observed and the coefficient (β) was found to be 1.2 × 10^-2 cm/GW. The nonlinear figure of merit of the dendrimer system is found to be 0.02 for intensities used in our experiments. The NLO responses of the individual structural components of the dendrimer molecule are provided to probe the structure-function relationships. The presence of a higher order, χ⁽⁵⁾, NLO effect was also detected and analyzed. The fast electronic processes of the dendrimer molecule and its components where also investigated by up-conversion luminescence spectroscopy. These studies provide the first probe into the ultrafast electronic NLO effects in organic dendrimers.