New Materials Directions for the Realization of Ultra-High Performance 3rd Order Non-Linear Optical Organics

Abstract : The overall objective of this project is to rationally design and create organic materials with high nonlinear refractive index and low single and two-photon absorption at wavelengths relevant to optical communications. Such materials would open up new capabilities in all-optical switching. Our approach to achieving this objective is to design and synthesize molecules with a twisted zwitterionic-ground-state structure that provides a multitude of low-lying closely-spaced excited states. These are coupled with different donor and acceptor groups and known 3rd-order active molecules to optimize real 3rd-order NLO response at wavelengths of interest. Coupling to the high density of states ofultrasmall metal nanoparticles and use of plasmonic field enhancement from anisotropic plasmonic nanostructures provide routes to further enhancement of the 3rd-order NLO response in these molecules. Head-to-tail aggregation of these molecules can also enhance 3rd-order NLO response through microscopic cascading of 2nd-order nonlinearity. Chiral control of nonlinearity bas also been studied.