A stable and switchable uniform lying helix structure in cholesteric liquid crystals

This investigation demonstrates an electrically switchable uniformly lying helix (ULH) stable state in cholesteric liquid crystal. A stable ULH state can be achieved by applying the low-frequency (30 Hz) pulse electrical field via an electro-hydrodynamatic effect. The ULH state can be stably maintained with a helical pitch in the visible range (450 nm-630 nm) and exhibit a tunable uniaxial crystal wave plate property under 1 kHz electrical field. The study examines the electro-optical property of ULH state and driving scheme for switching among the three stable states. A multi-stable and electrically switchable cholesteric liquid crystal can provide various optical properties and has extensive potential applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615293]