IS THE ELECTROMECHANICAL COUPLING THE DRIVING-FORCE FOR THE PERPENDICULAR DRIFT OF FIRST CLASS CHOLESTERIC FINGER

When a cholesteric liquid crystal is sandwiched between two horizontal glass plates with homeotropic anchoring, chiral patterns named choles teric fingers of first class, are known to occur. When a DC vertical e lectric field is applied, the Cholesteric Finger is then observed to m ove perpendicularly to its long-axis with a velocity V-perpendicular t o. In this paper, we prove analytically that this velocity may be rela ted with the Lehmann rotation effect, and that it may provide a new wa y to measure the electromechanical coupling coefficient.