We report on the development of photoaddressable cholesteric liquid crystal (CLC) mixtures capable of large range color tuning as well as direct on-off electrical switching. The continuously photoaddressable CLC mixtures are based on a high HTP azo-containing chiral material mixed with an off-the-shelf nematic liquid crystal (QL9/E44). By polymer stabilizing the QL9/E44 mixture, it is demonstra...

We demonstrated a low-voltage polymer-stabilized blue phase liquid crystal (BPLC) for phase-only modulation with a liquid-crystal-on-silicon (LCoS). A new device configuration was developed, which allows the incident laser beam to traverse the BPLC layer four times before exiting the LCoS. As a result, the 2π phase change voltage is reduced to below 24 V in the visible region. The response time...

We report a low-voltage and fast-response polymer network liquid crystal (PNLC) infrared phase modulator. To optimize device performance, we propose a physical model to understand the curing temperature effect on average domain size. Good agreement between model and experiment is obtained. By optimizing the UV curing temperature and employing a large dielectric anisotropy LC host, we have lower...

We demonstrated two liquid crystal diffractive waveplates: one optimized for near-infrared (1.06 µm), and another for mid-wave infrared (MWIR, 3~5 µm). By employing a low loss liquid crystal mixture UCF-M3, whose absorption loss is below 2% in the 4~5 µm spectral region, the grating achieves over 98% diffraction efficiency in a broad MWIR range. To switch the grating, both active and passive dr...

2014 We have studied the phase diagram of a binary system, constituted with a side-chain mesomorphic polymer and a monomer liquid crystal, very similar to the mesogenic groups in the polymer. The main results is the existence of a gap of miscibility in the nematic state, leading to the coexistence, at a same temperature, of two nematic phases. J. Physique LETTRES 43 (1982) L-671 L-675 15 SEPTEM...

Photo-induced molecular motion in a liquid crystal polymer film including azobenzene was studied by the heterodyne transient grating method. The film was confined in a liquid crystal cell, where it is a photomobile film under free-standing conditions. By observation of the refractive index change induced by a laser pulse, contraction of the film was observed on the order of several hundreds of ...

This tutorial review covers recent progress in the field of computer simulation of liquid crystals. The development of the main "molecular-based" models for liquid crystals is described. These include lattice models, coarse-grained single site models based on hard and soft interaction potentials, atomistic models and multi-site coarse-grained models. A brief historical review is followed by an ...

Dynamic light scattering was used to measure the azimuthal anchoring energy coefficient W(straight phi) of nematic liquid crystal (5CB) on photoaligning poly-(vinyl-cinnamate) layer. Measurements were repeated several times within two months. The results show that W(straight phi) increases in the first few days after filling the cell with liquid crystal. Then it remains approximately constant a...

We describe molecular-scale soft nanoimprint lithographic replication of rubbed polyimide substrates to form alignment layers for liquid crystal devices. Systematic studies of the surface relief morphology of the polyimide and molded structures in three different polymers illustrate good lithographic fidelity down to relief heights of several nanometers, and with some capabilities at the level ...

Phase separation in a polymer dispersed liquid crystal (PDLC), consisting of a main chain liquid crystal (E7) and polymethyl methacryhte (PMMA), was studied by means of light scattering and optical microscopy. The PMMAm mixture exhibits an upper critical solution temperature (UCST), overlapping with a nematic-isotropic transition of the E7 liquid crystal. Several temperature quenches were under...