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A low-voltage (< 10 V), high-transmittance (> 80%), submillisecond-response, and hysteresis-free polymer-stabilized blue-phase liquid crystal (BPLC) device with vertical field switching (VFS) and oblique incident light are demonstrated experimentally. Unlike the commonly employed in-plane switching in which the electric field is primarily in lateral direction and not uniform spatially, the VFS mode has uniform longitudinal field. As a result, the operating voltage is reduced by ∼ 3.2 × which in turn helps to eliminate hysteresis. The VFS mode is a promising candidate for the emerging BPLC display and photonic devices.

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Polarization-independent phase-only modulation of a polymer-dispersed liquid crystal ͑PDLC͒ is demonstrated. In the low voltage region, PDLC is translucent because of light scattering. Once the voltage exceeds a saturation level, PDLC is highly transparent and exhibits phase-only modulation capability. Although the remaining phase is not too large, it is still sufficient for making adaptive microdevices, such as microlens. A tunable-focus microlens for arrays using PDLC is demonstrated. This kind of microlens is scattering free, polarization independent, and has fast response time.

A fast-response and scattering-free homogeneously aligned polymer network liquid crystal (PNLC) light modulator is demonstrated at λ=1.55 μm wavelength. Light scattering in the near-infrared region is suppressed by optimizing the polymer concentration such that the network domain sizes are smaller than the wavelength. The strong polymer network anchoring assists LC to relax back quickly as the electric field is removed. As a result, the PNLC response time is ∼250× faster than that of the E44 LC mixture except that the threshold voltage is increased by ∼25×.

We have designed, synthesized, and evaluated the physical properties of some high birefringence (Án) isothiocyanato biphenyl-bistolane liquid crystals. These compounds exhibit Án $ 0:7{0:8 at room temperature and wavelength ¼ 633 nm. Laterally substituted short alkyl chains and fluorine atom eliminate smectic phase and lower the melting temperature. The moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. A eutectic mixture based on those compounds was formulated and its physical properties evaluated. The simulated absorption spectra agree reasonably well with the measured results.

Several dialkyl and fluoro bis-tolane liquid crystals were synthesized and their physical properties evaluated. These highly conjugated liquid crystals exhibit a wide nematic range, small heat fusion enthalpy, high birefringence, and relatively low viscosity. Their excellent compatibility with commercial cyano mixtures makes these liquid crystals attractive for many electro-optic applications.

A polarization-independent phase-only liquid crystal (LC) phase modulator using a double-layered structure is demonstrated. Two orthogonal LC layers are separated by two ultra-thin anisotropic polymer films. The anisotropic polymeric films not only separate the LC layers but also provide good molecular alignment. As a result, a polarization-independent phase modulator with 2pi phase shift is achieved at 9Vrms and 8.1pi at 40Vrms using a 12-microm-thick E7 LC layers. This operating voltage is ~10X lower than that using a conventional 0.3-mm-thick glass separator.