Twisted homogeneously planar-aligned nematic liquid-crystal cells are cooled into the smectic- A phase. The expected defective structure does not form. Instead the cells still show good optical-guiding characteristics. Exploration of the cells using a half-leaky guided-mode arrangement reveals that the liquid-crystal phase separates into three or more regions. Adjacent to both the upper and low...

We derive the amplitude equation, in the weakly nonlinear regime, for an optical wave packet that propagates in an initially undistorted nematic liquid crystal. By using the dyad representation Q i j , we find the retarded and nonlocal equation for the nematic configuration and solve it in Fourier space. This allows us to calculate the amplitude dependent dispersion relation for a nematic liqui...

We present a mean field theory to describe phase behaviors in mixtures of a polymer and a cholesteric liquid crystal under an external magnetic or electric field. Taking into account a chiral coupling between a polymer and a liquid crystal under the external field, we examine twist-untwist phase transitions and phase separations in the mixtures. It is found that a cholesteric-nematic phase tran...

In order to develop a fine angular beam steering technique (milliradian and less), we propose a nematic liquid crystal cell with a continuous gradient of the refractive index. This continuous gradient is controlled by applying the driving voltage to non-patterned indium-tin oxide electrodes. We employed the dual-frequency nematic liquid crystal in the cell with high pretilt alignment. The exper...

2014 A new experimental method to measure the twist elastic constant of nematic liquid crystals is proposed. The method is based on a direct measurement of the torque which the nematic liquid crystal exerts on the surfaces when a magnetic field is applied. The reliability of this technique is tested by measuring the twist elastic constant of the nematic liquid crystal 4-n-pentyl-4’-cyanobipheny...

We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro...

Phenylene-thiophene-based liquid crystalline π-conjugated copolymers bearing mesogenic groups as side chains were synthesized via a Stille polycondensation reaction and confirmed to exhibit a nematic liquid crystal phase at appropriate temperatures. The formation of a nematic phase, but not a smectic phase indicates cooperation of the main chain and side chain in the formation of a nematic main...

The elusive biaxial nematic liquid crystal phase was recently discovered in a family of substituted oxadiazoles. Our investigations of these materials show that the achiral biaxial nematic phase can segregate into chiral domains of opposite handedness, thereby demonstrating that the liquid-like nematic phase exhibits the properties of a conglomerate.

tering and the polymer dispersed liquid crystal display. (E) 194. "The Quartz Watch with Digital Readout," H. R. Crane, The Physics Teacher 32(5), 298-299 (1994). This article describes the operation of a twisted nematic display and is written for high school and college physics educators. (E) 195. "Liquid-Crystal Displays: Molecules at Work," G. P. Crawford and R. J. Ondris-Crawford, Physics E...