Ionically self-assembled monolayer (ISAM) films have been shown to spontaneously produce noncentrosymmetric ordering that gives rise to a substantial second order nonlinear optical (NLO response. Previously, the ISAM films for NLO response consisted of bilayers of oppositely charged polymers whose thickness can be controlled through variation of pH and ionic strength of the immersion solutions. Here, we present an approach that replaces the NLO-active polymer layers with layers of monomeric chromophores containing ionic and covalent bonding sites. We have examined the effect of the pH of the immersion solutions on the orientation the of monomeric chromophores and demonstrated bulk polar ordering with X(2) values six times larger than quartz.
© 2002 Optical Society of AmericaPDF Article