Transverse surface-induced polarization at the interface between a chiral nematic liquid crystal and a substrate

A chiral nematic liquid crystal that is tilted by an angle theta(i) with respect to a substrate is subjected to an ac electric field at frequency omega applied parallel to the substrate. The nematic director is found to oscillate azimuthally about the normal to the liquid crystal-substrate interface at frequency omega, indicating that a nonzero polarization perpendicular to the molecular tilt plane exists at the interface. The interfacial polarization, anchoring strength coefficient, and bulk viscosity are obtained by measurements of the oscillation amplitude as a function of omega.