Electrooptical chromophores for nonlinear optical and photorefractive applications

Abstract

Optimization strategies for electrooptical (EO) chromophores for nonlinear optical (NLO) and photorefractive (PR) applications were studied. A new series of dyes, thiazolydenemalononitrile, was synthesized. The NLO and PR figures-of-merit cannot be optimized simultaneously and different strategies will need to be followed to optimize EO chromophores for poled polymers and PR materials. The best NLO chromophores are polyene-like merocyanines with large dipole changes upon optical excitation and strong positive solvatochromism. The best PR chromophores are neutro-cyanines located highly slightly beyond the cyanine limit, where high dipole moments and large polarizability anisotropies combine in the most favorable way.