Ultrafast Third-Order Non-Linear Optical Processes in Polymeric Films

摘要

This paper includes selective results from our comprehensive program in nonlinear optical effects in organic molecules and polymers. The focus of our study has been on the third order effect. We have calculated microscopic nonlinearities of organic molecules in several series of conjugated structures using ab-initio SCF approach coupled with the finite field method. The effects of increase in the Pi-electron conjugation length and molecular conformation, as well as the heavy atom effect and the role of substituents have been investigated in order to derive an understanding of molecular structure-property relation so that structural parameters associated with enhanced optical nonlinearities can be identified. This theoretical study has been complemented with the measurements of optical nonlinearities in subsequently built and systemically derivatized structures. (Reprint)