Poled Polymeric Nonlinear Optical Materials. Enhanced Second Harmonic Generation Stability of Cross-Linkable Matrix/Chromophore Ensembles

摘要

The creation and stabilization of microstructural acentricity is central to the successful design of polymeric materials with large quadratic optical nonlinearities. While significant preferential alignment of chromophore molecules doped into polymer glasses can be achieved by electric field poling, the pronounced temporal instability of such alignment, and hence the temporal instability of second harmonic generation (SHG) characteristics, remains an unsolved problem. These disorientation effects are a natural consequence of the dynamic processes by which glassy polymers undergo physical aging/relaxation to minimum free volume. We recently reported a promising approach to chromophore immobilization in which high-beta, nonlinear optical (NLO) chromophores are covalently bound to the backbone of a high-Tg, TB glassy polymer. We communicate here the development of a second, complementary approach in which a high-beta guest chromophore is dispersed in an optically transparent host matrix that can then be simultaneously poled and chemically cross-linked. Reprints. (mjm)