Determination of the Cholesteric Screw Sense

Abstract

If a cholesteric liquid crystal is placed between a glass plate with planar alignment and a spherical lens with concentric surface alignment, a double spiral disclination line appears. The spiral rotation sense depends on the helix screw sense of the cholesteric phase and the radial distance between the disclination lines on the pitch magnitude. A theoretical calculation of the form of the spiral disclination lines is given and compared with experimental results.