Poled sol-gel materials with heterocycle push-pull chromophores that confer enhanced second-order optical nonlinearity

Hybrid organic-inorganic materials doped with zwitterionic push-pull chromophores with high hyperpolarizability have been synthesized by a sol-gel procedure. A large chromophore concentration was reached by using N-(hydroxyethyl)carbazole as a physical spacer (preventing the dye aggregation). Spain-coated doped films were electrically poled and second harmonic generation measurements performed in situ. During the thermally assisted polling under a N-2 atmosphere,only the carbazole molecules degraded. Second-harmonic generation measurements gave an estimation of the nonlinear-coefficient, r(33), of 38 pm V-1 at 1064 nm.