Optical phase shift of polymer-dispersed liquid crystals

Abstract

We report a detailed study of the optical phase shift induced by a polymer-dispersed liquid crystal subjected to a low-frequency electric field. A relationship between the optical phase shift and the droplet and sample order parameters ${\mathit{S}}_{\mathit{d}}$ and ${\mathit{S}}_{\mathit{f}}$ is worked out in order to explain the experimental data obtained using an ellipsometric technique. The measurements taken for several incidence angles are in very good agreement with the expected behavior if an increase of the droplet order parameter is also considered when increasing the field. The method appears suitable to study reorientation phenomena in polymer-dispersed liquid crystals overcoming the problems due to light scattering in these materials.