New organic non-linear optical materials of stilbene and diphenylacetylene derivatives

Abstract

We report a series of new optically non-linear organic molecules of stilbene and diphenylacetylene derivatives. We have measured their powder second-harmonic generation efficiency and, in certain cases, the second-order molecular polarizability, β. This series of molecules is characterized by: (1) very large non-linearity, (2) high probability of forming non-centrosymmetric crystal structures, and (3) polymorphism. A number of relatively weaker donors: methoxy, bromo, and iodo, have been identified as effective moieties to enhance the intrinsic molecular non-linearity. Using weak donors to prepare highly non-linear optical materials provides advantages of having better optical transparency and high probability of forming acentric structures.