An electrooptic effect from liquid crystal monolayers

We report on electrooptic measurements on Langmuir-Blodgett (LB) monolayers of a 1/1 mixture of n-octyl-cyanobiphenyl (8CB) and stearic acid. The requ ired sensitivity is achieved by depositing the LB-film on a thin gold layer and measuring the field-induced shift of the surface plasmon resonance. Th e existence of a finite electrooptic coefficient is proof of polar anisotro py in the monolayer. The electrooptic coefficient depends on details of the deposition process and does not change with temperature or frequency of th e applied electric field.