ELECTROCLINIC EFFECTS IN A HOMOGENEOUSLY ALIGNED SMECTIC-A CELL

The electroclinic effect, in a material having a first order S-A to S- C transition, is studied using the half leaky guided mode geometry. U sing an approximately 1 mu m thick, homogeneously aligned cell, the vo ltage induced director twist is characterized at a few temperatures in the S-A phase. The mean field theory readily explains the data record ed at low fields where a linear dependence on voltage is found. Howeve r, at higher fields, an unexpected saturation occurs which is most lik ely caused by the influence of strong surface anchoring forces.