Electro-optical switching and order parameter measurements of dual-frequency nematic liquid crystals: regimes of thin and thick cells.

Liquid crystals utilized in conventional display applications typically have a layer thickness of less than 10 µm. However, emerging non-display applications of liquid crystals require thicker material layer with faster response. Electro-optical performance of relatively thin liquid crystal cells is well-documented, butt little is known about the properties of thicker layers. Also to address the need for the fast electro-optical switching a dual frequency liquid crystals are investigated. We are presenting the electro-optical response of dual-frequency nematic liquid crystals using a broad range of the cell thickness (2–200 µm). Two regimes of electro-optical switching of dual-frequency nematics are observed and analyzed. To uncover the origin of the observed two regimes of electro-optical switching, measurements of the orientational order parameter of dual frequency nematic liquid crystals were carried out over the same range of thicknesses. The non-monotonous dependence of the order parameter S on the cell thickness obtained for relatively thin layers (< 60 µm), and is followed by a rapid monotonous decay for thicker (60-200 µm) samples. This provides a basis for understanding of two regimes of electro-optical switching of thin and thick layers of dual frequency nematics.