This is the 2015 MidCareer Researcher Award Talk, presented by Seth R. Marder, Georgia Institute of Technology.

Dr. Marder was presented with the MRS MidCareer Researcher Award “For establishing fundamental relationships between the chemical structure of organic molecules and their optical and electronic properties, thereby profoundly impacting how the scientific community designs optimized molecular structures for use in nonlinear optical applications”.

In Marder's presentation the design guidelines for molecules and materials that have large twophoton absorption crosssections and large “real” thirdorder susceptibilities for all optical switching were provided. Specifically, molecules with large twophoton absorption crosssections, d, are in great demand for a variety of applications including twophotonexcited fluorescence microscopy and threedimensional opticaldata storage. These applications utilize the quadratic scaling of the rate of twophoton absorption with input intensity, which allows for the excitation of chromophores with a high degree of spatial selectivity in three dimensions through using a tightly focused laser beam. A strategy for the design of molecules with large twophoton absorption crosssections, d, has been developed, which is based on the concept that symmetric charge transfer (upon excitation), either from the ends of a conjugated system to the center or vice versa, is correlated to enhanced values of d. In addition, the synthesis and characterization of materials with large thirdorder nonlinear susceptibility, ?(3), were discussed.