We experimentally demonstrate fast flexoelectro-optic switching in a liquid crystal cell containing bimesogen-doped and polymer-stabilized cholesteric. The device exhibits a response time of less than 0.7 ms and with low hysteresis and color dispersion which is suitable for potential applications including field-sequential color displays.
Herein, we report the enhancement of electro-optical performances of nanoparticle embedded liquid-crystal devices in the laser speckle pattern reduction, enhancement of viewing angle, and that of color gamut by doping the nano-particles(NPs) of PγCyclodixtrin-ZrO<sub>2</sub> (Shiraishi lab) and Aerosil R-812(EVONIK) into the liquid crystal devices. This report will be done through updating of previous work [1-4] in particular giving physical modeling and simulations.
We demonstrate a liquid crystal Fresnel lens (LCFL) with a surface relief structure which has the binary switching property and the merit of low voltage driving. The surface relief structure is fabricated by photopolymerization of a polymer-precursor initiated by ultra-violet light onto a solid cylindrical Fresnel lens with desired optical power. A liquid crystal (LC) layer is sandwiched between a pair of polymer Fresnel lens deposited with planar alignment layers with orthogonal rubbing directions. The ordinary refractive index of LC is chose to be close to the refractive index of the polymer. At voltage-off state, when the polarization of light is parallel to the long axis of LC molecules, the refractive index mismatch of liquid crystals and polymer Fresnel lens enables the focusing of LCFL. At voltage-on state, the LCFL is a slab with homogenous refractive index because of the index matching between LC and polymer. With the benefit of twisted nematic structure, the voltage requirement is significantly low (~6V) for LCFL. The low-voltage binary beam shaping of laser and magnifying lens function using LCFL are experimentally demonstrated in this paper. Polarization-independent LCFL is achievable with a double-layered approach.
A biosensor for the concentration of high-density lipoprotein (HDL) in human serum on a liquid crystal and polymer composite film (LCPCF) is demonstrated. The sensing mechanism is based on a polar-polar interaction between orientation of LC directors and HDL in human serum. The concentration of polar HDL in human serum affects the orientations of LC directors at the interface between LCPCF and the human serum. In addition, the surface free energy of LCPCF changes with the applied voltage due to the electrically tunable orientations of LC directors anchored among the polymer grains of LCPCF. As a result, the droplet motion of human serum on LCPCF under applied voltages can sense the concentration of HDL in human serum.