Cooperative liquid-crystal alignment generated by overlaid topography

Optical vortices generated by dislocations in a cholesteric liquid crystal.

We report the observation of optical vortices in a laser beam propagating through the stripe pattern of a cholesteric liquid crystal. The liquid crystal is confined in a cell with homogeneous boundary conditions and forms a diffraction phase grating. Optical vortices are produced by edge dislocations of the cholesteric grating. The vortices show up as spots of zero light intensity in the diffra...

Photopatterning of Liquid Crystal Alignment Cells

Surface Dipole Control of Liquid Crystal Alignment.

Detailed understanding and control of the intermolecular forces that govern molecular assembly are necessary to engineer structure and function at the nanoscale. Liquid crystal (LC) assembly is exceptionally sensitive to surface properties, capable of transducing nanoscale intermolecular interactions into a macroscopic optical readout. Self-assembled monolayers (SAMs) modify surface interaction...

Tunable command layers for liquid crystal alignment.

A simple method for the construction of a stable, tunable, self-assembled command layer for liquid crystal display purposes is described. A pyridine-functionalized oligosiloxane spontaneously forms an anisotropic, grooved surface on indium-tin-oxide, enabling it to align liquid crystalline molecules. The pyridine functions act as seeds for the epitaxial growth of stacks of highly ordered zinc p...

Controlling the Alignment of Polyimide for Liquid Crystal Devices

Liquid crystal (LC) devices have been popular for use in photonics products, such as displays for mobile phones, televisions and computers. As shown in Fig. 1, a typical LC device consists of a thin LC layer sandwiched between a pair of indium tin oxide (ITO) conducting glass substrates with a cell gap of few micrometers. Polyimide (PI) as a polymeric material characterized by its outstanding m...