Periodic defects lines in liquid crystal cell guided by polarization holograms at an aligning surface

Defect lines arrays are created in liquid crystal exploiting periodic arrangements of twisted domains with opposite handedness. The defect lines self-organize in a planar cell guided by a polarization hologram recorded in one aligning substrate that provides planar periodic alignment. Depending on the relationship between the cell thickness d and the hologram pitch Lambda, the array period can be either Lambda or 2 Lambda. An external voltage enables to switch the spatial periodicity of the defect lines from 2 Lambda to Lambda and also to control their shape and location. A modeling of the observed twisted arrangements is reported.