A PRELIMINARY INVESTIGATION OF THE ANOMALOUS OUT-OF-PLANE TILT ALIGNMENT IN AN ORTHOGONAL-TWIST FERROELECTRIC LIQUID-CRYSTAL CELL USING THEPRISM-COUPLING TECHNIQUE

Recent prism-coupling results are presented which clearly demonstrate that in ferroelectric liquid crystal cells, prepared with the alignmen t directions of the two surfaces orthogonal, with sputtered indium tin oxide conductive layers and spun polyimide alignment layers, there is no out-of-plane tilt of the liquid crystal optic axis. Unlike most te chniques which give an integrated optical response throughout a cell, the prism-coupling technique allows a separate analysis of in-plane an d out-of-plane tilt. Conventional optical polarized microscopy yields good lateral resolution but poor section resolution. For a uniform sam ple we can obtain information on the section (across the cell) resolut ion. We report that an optical dielectric tensor configuration is form ed in which the major optic axis lies in the plane of the surface acro ss the cell, but that as expected, in an orthogonal-twist cell, there is no axis of preferred alignment within this surface plane.