Second‐order nonlinear optical response of thin films containing organic chromophores. Theoretical aspects

Abstract

AbstractThis paper discusses some theoretical aspects associated with the unusual second‐order nonlinear optical response of chromophoric self‐assembled stilbalzolium superlattices, and of (N,N‐dimethylamino)‐4‐nitrostilbene (DANS)‐doped glass polymers poled in an “in‐plane” configuration. It is found that the bulk nonlinearity of such materials strongly depends upon specific chromophore interactions. While for the stilbalzolium superlattices the supramolecular hyperpola‐rizability is strongly affected by the ion‐pair configuration, the formation of (formally) centrosymmetric charged chromophore aggregates is likely responsible for the observed anomalous strong nonlinearity in DANS‐doped in‐plane poled polymers. The simple “chromophore gas” model is thus inadequate to describe the non‐linearity of such materials.