Quasidivergent nematic surface electroclinic effect.

A polyimide coated substrate is treated so that vertical liquid crystal alignment (theta=0) obtains over the temperature range T(NA)< T < T(a), where T(NA) is the nematic-smectic-A transition temperature. When the cell is filled with a chiral liquid crystal whose helical pitch is unwound (surface stabilized), application of an in-plane electric field for T(NA)< T < T(a) induces a nonzero polar tilt theta proportional to E of the liquid crystal director at the surface, where the tilted orientation propagates elastically into the bulk. On heating toward T(a), this surface electroclinic response becomes large, corresponding to the onset of a surface tilt transition at T(a) from theta=0 to nonzero theta.