Spontaneous and stable uniform lying helix liquid-crystal alignment

The flexoelectro-optic effect in the uniform lying helix (ULH) geometry could provide many advantages over existing liquid-crystal technologies, however reliably forming the ULH has been problematic. Here, we achieve spontaneous, stable, and repeatable ULH alignment for materials with both positive and negative dielectric anisotropy in devices ranging from 1 to 7 mu m in thickness without the need for any field application or flow-induced alignment, using a combination of weak homeotropic alignment conditions and unidirectional grooved surface profiles. The technique requires slow cooling from the isotropic phase and through the blue phase. Devices made using the technique display sub-millisecond and linear electro-optical responses. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4784016]