An electro-optic device based on field-controlled anchoring of a nematic liquid crystal

A surface-controlled electro-optic device using a nematic liquid crystal enclosed between two thin spaced glass plates is presented. Modulation angles of the optic axis up to more than 70° can be achieved even for small applied voltages. The switching of the optic axis occurs with a large component in the plane of the sample even though the electric field is applied normal to the sample surfaces. The effect seems to be driven by the dielectric coupling of the liquid crystal molecules with the applied electric field. The field induced switching process is governed by the bounding surfaces that have been covered with obliquely evaporated SiOx. The mechanism of the phenomenon is briefly discussed.