Blue phase liquid crystals exhibit unique properties which are used in the new type of display. A blue-phase liquid crystal display was first presented commercially by Samsung in 2007. The blue-phase-three-color pixel display eliminates the need for color filters. This type of display uses blue-phase multi-component liquid crystal. Considering the one-component systems, it turns out that they are stable only in a very narrow range of temperatures between the isotropic and the chiral nematic phase (about 1 K). In 2005, a wide temperature range BP multi-component system was reported by researchers from the University of Cambridge. There are still several unsolved problems left. One of them is chemical stability and reliability. Therefore, the knowledge of molecular dynamics of blue phase liquid crystal is a prerequisite for understanding of blue-phase multi-component system. Understanding the molecular dynamics of a single component liquid-crystalline blue phase system can facilitate the solution of these problems. We present the molecular dynamics investigation of 4-(2-methylbytyl)phenyl 4-(4-octylphenyl) benzoate (CE8), which may be a good candidate to form materials suitable for blue-phase liquid crystal displays.
A laser diode reliability test based on the measurements of the low-frequency optical and electrical noise, and their correlation factor changes during short-time ageing is presented. The noise characteristics reveal obvious differences between the stable and unreliable lasers operated near the threshold region. An excessive Lorentzian type noise with negative correlation factor at the threshold could be one of the criteria for identifying unreliable lasers. The behavior of unreliable lasers during ageing could be explained by migration of point recombination centres at the interface of an active layer, and by the formation of defect clusters.
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