Color shift on off-axis angles is key issue of the cholesteric liquid crystal (CLC) polarizer. In this paper, color shift issues
on various azimuthal and viewing angles of back light unit assembled with CLC polarizers are analyzed by optical
simulation. We found that smaller NZ value of quarter-wave plate (QWP) of our samples will compensate the color shift
issue more efficiently. Although abnormal dispersion type QWP gives the best performance at the on-axis viewing
angles, at large viewing angle its color shift is depending on azimuthal angle and bandwidth of CLC polarizers. Besides,
a single layer type CLC polarizer of gradient pitch over a shorter bandwidth has better color coordinate property also be
We present a sensitive nano-optical fiber biosensor made by shaping a fiber to form a taper with a tip size under 100 nm. A 40-nm-thick layer of gold is coated around the tapered fiber and a surface plasmon wave is excited near the tip to achieve a sensitivity of the reflective index unit of ~4000 (% RIU–1) in the intensity measurement. A 3-D coded finite-difference time-domain approach verifies the excitation of the surface plasmon wave and the differences among its intensities in media of various refractive indices. The nanotip fiber sensor has the merits of a low background light and an ultrasmall detection region. Only a microliter of sample solution is required for detection.
New chiral organic acid 1 and alcohol 2 synthesized from natural lactate and (S)-1-iodo-2- meyhylbutane were used as chiral block for preparing ferroelectric liquid crystals. Six series of chiral liquid crystals were synthesized to study the molecular structure-liquid crystal phase relationship. Different liquid crystal phase sequence K-Sc*-SA-I, K-Sc*-N*-I, or K-N*-I is formed among them. The thermal stability of Sc* phases observed is high. These new FLCs and their mixtures could be useful for practical use. The results also indicate that compounds 1 and 2 could be helpful for preparing new FLCs.