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Liquid Crystals - Science topic

Materials in intermediate state between solid and liquid.
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Publications related to Liquid Crystals (10,000)
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Article
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We report a three-dimensional (3D) molecular orientation control of a liquid crystal organic semiconductor (LC-OSC) based on the long-range ordering characteristic of an LC material. To this end, a synthetic LC-OSC molecule, MeOPh-BTBT-C8, with a fluidic nematic (N) phase that is essential for alignment control over a large area and a smectic E (Sm...
Article
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Pancharatnam–Berry (PB) phase has become an effective tool to realize the photonic spin Hall effect (PSHE) in recent years, due to its capacity of enhancing the spin-orbit interaction. Various forms of PSHEs have been proposed by tailoring the PB phase of light, however, the propagation trajectory control of the separated spin states has not been r...
Article
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Liquid crystal displays (LCDs) and photonic devices play a pivotal role to augmented reality (AR) and virtual reality (VR). The recently emerging high-dynamic-range (HDR) mini-LED backlit LCDs significantly boost the image quality and brightness and reduce the power consumption for VR displays. Such a light engine is particularly attractive for com...
Article
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To unveil a novel switching mechanism in liquid crystal (LC)-based phase shifters for the THz range, we analyse how the dimensions of the electrode structures enable a new type of switching, namely, THz in-plane and THz out-of-plane (TIP–TOP) switching. Specifically, we determine how varying these electrode dimensions influences the LC in-plane sta...
Article
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Spatial light modulators (SLMs) are the most relevant technology for dynamic wavefront manipulation. They find diverse applications ranging from novel displays to optical and quantum communications. Among commercial SLMs for phase modulation, Liquid Crystal on Silicon (LCoS) offers the smallest pixel size and, thus, the most precise phase mapping a...
Article
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In this work a ferroelectric liquid crystal (FLC) modulator with a non-standard large switching rotation angle, close to 90∘, is fabricated and characterized. The modulator acts as a switchable wave-plate with an in-plane rotation of the principal axis under the action of a bipolar voltage. In the ideal situation of half-wave retardance, the device...
Article
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The feasibility of replacing quartz powder (QP) with liquid crystal display glass powder (LCDGP) in ultra-high-performance concrete (UHPC) matrix is discussed through the investigation of pozzolanic reactivity, packing density, compressive strength, pore structure, hydration behavior, pullout resistance, and direct tensile tests. The pozzolanic cha...
Article
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In visible light communication systems, the ability to suppress interference caused by other light sources is a major benefit towards performance improvements. Especially for large transmitter arrays or even multi-cell arrangements, the interference problem needs to be handled. In previous work, we have presented a liquid crystal display (LCD) used...
Article
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Solar energy is widely used for electricity generation, heating systems, and indoor environment daytime illumination. Indeed, large amounts of sunlight energy remain insufficiently used. In this work, we aim at employing sunlight energy for data transmission as a green option for wireless communications. Being emitted by an uncontrollable source, t...
Article
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A pressure gradient caused by the local field-induced reduction of the effective molecular volume results in a flow of the nematic liquid crystal (NLC). Here, the hydrodynamics of homeotropically aligned NLC molecules under the influence of this pressure gradient was studied theoretically. The equations describing the system were written and solved...
Article
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As we move from the industrial age to the information age, nowadays, the opportunity to access personal information in public increases as personal computers (PCs), cell phones, automated teller machines (ATM) and other portable display devices have come into wider use, so it is well suited for these liquid crystal displays (LCDs) to switch between...
Conference Paper
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This system seeks to demonstrate a design that can automatically detect, alert, and regulate gas leakage by employing an exhaust fan to suck the gas away from the premises when there is a leakage and a sprinkler to put out the fire if there is a fire breakage. When a gas leak is discovered, the alarm sounds, the exhaust fan pulls the gas outside, a...
Conference Paper
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By using an exhaust fan to remove gas from the area when there is a leak and a sprinkler to douse a fire in the event of a fire break-out, this system aims to demonstrate a design that can automatically detect, alert, and control gas leakage. In the event of a gas leak, an alarm is activated, an exhaust fan draws the gas outside, and a liquid cryst...
Conference Paper
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In this research, the smart home and management system use D.C batteries as their source of power. When the battery is fully charged, it can work for 2 to 3 days before it runs low. When you power the system, the title of the research is displayed on the LCD, and the maximum temperature is displayed. It will also show you that nobody is inside t...
Article
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Smart channels that manipulate liquid motion by anisotropic shape changes represent a promising candidate to construct microfluidics for biochemical analysis. However, the existing systems fail to provide a platform for solid exchange mediums to interact with multiple liquid phases, which is a universal technique to effectively extract, enrich, and...
Article
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The Doi–Onsager molecular theory is capable of providing a rather accurate description of the local behavior of molecules; however, its computation is extremely time-consuming, since some higher-dimensional variables are typically involved. Therefore, establishing a computable reduced model that can capture essential physical properties is an impor...
Article
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In typical turbulent flow problems, detailed heat transfer coefficient (h) maps obtained through short-duration experiments are based on inverse heat transfer methods that take the wall temperatures measured via liquid crystals or infrared thermography as input, and an error minimization routine is adopted to determine the best value of h that sati...
Article
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High dynamic range (HDR) displays based on liquid crystal panels require local dimming algorithms to reproduce content with high fidelity and HDR. However, most local dimming algorithms are developed by using hand-crafted features and most of them focus on low dynamic range images rather than HDR images. In addition, few local dimming algorithms ca...
Article
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This paper presents a study of the influence of bimetallic layer covers of a tapered optical fiber surrounded by a low refractive index liquid crystal on the properties of light propagation in the taper structure. This research follows previous works on the effect of mono metallic thin films (Au and Ag). In this case, the total thicknesses of the b...
Article
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Direct laser writing (DLW) in liquid crystals (LCs) enables a range of new stimuli-responsive functionality to be realized. Here, a method of fabricating mechanically tunable diffraction gratings in stretchable LC gels is demonstrated using a combination of two-photon polymerization direct laser writing (TPP-DLW) and ultraviolet (UV) irradiation. R...
Article
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Colloidal liquid crystals are an emerging class of soft materials that naturally combine the unique properties of both liquid crystal molecules and colloidal particles. Chiral liquid crystal blue phases are attractive for use in fast optical displays and electrooptical devices, but the construction of blue phases is limited to a few chiral building...
Article
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For any bounded smooth domain Ω⊂R2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \subset \mathbb {R}^2$$\end{document}, we will establish the convergence of wea...
Article
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The hydrogen-bonding interaction is studied in imidazolium-based mesogenic ionic liquids in their isotropic, smectic, and solid phases and in a nanoconfined state by proton solid-state nuclear magnetic resonance (NMR). In the smectic phase, the more basic anions form stronger hydrogen bonds. A small decrease of H-bonding in the mesophase with respe...
Article
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The mesogen orientations of liquid crystals are sensitive to the nature of the contacting surface. For side chain liquid crystalline polymer (SCLCP) films, most investigations have been conducted for thin films formed on a solid substrate surface such as glass, quartz and metal oxides, and little knowledge has been accumulated for SCLCP films whose...
Article
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Fouling control coatings (FCCs) are used to prevent the accumulation of marine biofouling on, e.g., ship hulls, which causes increased fuel consumption and the global spread of non-indigenous species. The standards for performance evaluations of FCCs rely on visual inspections, which induce a degree of subjectivity. The use of RGB images for object...
Article
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Eliminating topological defects to achieve monodomain liquid crystals is highly significant for the fundamental studies of soft matter and building long-range ordered materials. However, liquid crystals are metastable and sensitive to external stimuli, such as flow, confinement, and electromagnetic fields, which cause their intrinsic polycrystallin...
Preprint
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The isotropic to ferroelectric nematic liquid transition had been theoretically studied over one hundred years ago, but its experimental studies are rare. Here we present polarizing optical microscopy studies and theoretical considerations of ferroelectric nematic liquid crystal droplets coexisting with the isotropic melt. We find that the droplets...
Article
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It has been shown that a nonchiral anisotropic macromolecule embedded in a chiral dielectric solvent possesses an effective optical activity proportional to the optical activity of the solvent. As a result, there exists an effective chiral interaction between the macromolecules, which creates a torque acting on the primary axes of the two interacti...
Chapter
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Liquid crystal spatial light modulators (LC-SLMs) have gained substantial interest of the research fraternity due to their remarkable light modulation characteristics in modern imaging applications. Replacing the conventional optical elements from the SLM-based computer-generated holograms (CGHs) is a trending approach in modern digital holographic...
Article
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The development of biosensing platforms has been impressively accelerated by advancements in liquid crystal (LC) technology. High response rate, easy operation, and good stability of the LC droplet-based biosensors are all benefits of the long-range order of LC molecules. Bioprobes emerged when LC droplets were combined with biotechnology, and thes...
Article
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Self-regulation is an essential aspect in the practicality of electronic systems, ranging from household heaters to robots for industrial manufacturing. In such devices, self-regulation is conventionally achieved through separate sensors working in tandem with control modules. In this paper, we harness the reversible actuating properties of liquid...
Article
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Electro-optical tuning metasurfaces are particularly attractive since they open up routes for dynamic reconfiguration. The electro-optic (EO) modulation strength essentially depends on the sensitivity to the EO-induced refractive index changes. In this paper, lithium niobate (LiNbO3) metasurfaces integrated with liquid crystals (LCs) are theoretica...
Preprint
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Birefringence, an inherent characteristic of optically anisotropic materials, is widely utilized in various imaging applications ranging from material characterizations to clinical diagnosis. Polarized light microscopy enables high-resolution, high-contrast imaging of optically anisotropic specimens, but it is associated with mechanical rotations o...
Article
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Deliberate manipulation of topological defects is of particular interest for liquid crystal applications. For example, surface bistability occurs in the grating aligned Zenithal Bistable Device due to the stabilisation of ±½ defects at the points of high surface curvature. Conventional latching between continuous and defect states has previously be...
Article
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This study aims to analyze the development trends of intelligent device interface improvements, specifically the car dashboards, by applying liquid crystal display technology. The methodology used in this study is mainly a comparison and analysis of the improvements that have been made. The objects in the study were several old version dashboards d...
Article
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Self-assembled architectures of soft matter have fascinated scientists for centuries due to their unique physical properties originated from controllable orientational and/or positional orders, and diverse optic and photonic applications. If one could know how to design, fabricate, and manipulate these optical microstructures in soft matter systems...
Preprint
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Sessile droplets of a ferroelectric nematic liquid crystalline material were exposed to surface electric fields produced by pyroelectric and photogalvanic (photovoltaic) effects in X-cut iron-doped lithium niobate crystals. The resulting dynamic processes were monitored by polarization optical (video)microscopy (POM). During heating/cooling cycles,...
Article
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Topological physics relies on Hamiltonian’s eigenstate singularities carrying topological charges, such as Dirac points, and – in non-Hermitian systems – exceptional points (EPs), lines or surfaces. So far, the reported non-Hermitian topological transitions were related to the creation of a pair of EPs connected by a Fermi arc out of a single Dirac...
Article
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Liquid crystal (LC) research in China started during the Cultural Revolution years in the late 1960s. It was motivated partly by the potential application in liquid-crystal display (LCD) digital television (TV) and movies, deemed good for the government’s political propaganda agenda. The large-screen LCD TV/movie project was initiated and done at t...
Book
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South Korea is a unique blend of old and new, ancient and modern, nature and technology. That`s why it`s nicknamed the Land of the Morning Calm South Korea is the leader in the high-tech progress with companies like Samsung, LG, SK, Hyundai, POSCO and other twelve on Fortune Global companies. Cutting edge technologies through the country`s investm...
Article
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Beam‐steering device using liquid crystal (LC) grating with field‐induced twist deformation, which has symmetric LC director distribution, is demonstrated. The proposed LC cell can convert the polarizations without multidomain LC alignments, and the polarization of the output light can also be changed with different input polarization. Therefore, t...
Article
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A polarization-probe polarization-imaging (PPPI) system was developed for the near-infrared (NIR) regime. This system comprises two components operating as a polarization generator and a polarization analyzer to enable polarization image capture under polarized light illumination. The captured polarization images contain considerable object informa...
Preprint
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We study axially symmetrical 3D skyrmionic particles (torons, hopfions) in a thin homeotropic cell filled with a cholesteric liquid crystal. In this case, the contribution of the chirality term on far distances becomes small and a 3D skyrmion can be described as a very specific particle in nematic with multipole moments of different chiralities. We...
Article
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The analytical distribution of the electric field in a micro-lens made of polymer-stabilized blue phase liquid crystals (PS-BPLCs) between two electrodes has been derived, and ray bending and focusing for the o (ordinary) and e (extraordinary) rays caused by the field-induced extended Kerr effect on the PS-BPLC have also been calculated. Those calc...
Article
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A facile approach to block copolymer (BCP) domain orientation control in thin films has been demonstrated by employing a BCP with liquid crystalline semifluorinated side chains by tuning the composition of the copolymers of the bottom surface layer (BSL). 1H,1H,2H,2H-Perfluorodecanethiol was attached to a precursor polymer, polystyrene-block-poly(g...
Article
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The camera and projector are indispensable hardware parts of a color fringe projection 3D measurement system. Chromatic aberration between different color channels of the projector and camera has an impact on the measurement accuracy of the color fringe projection 3D profile measurement. There are many studies on camera calibration, but the chromat...
Article
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Recently, various chiral aromatic compounds, including chiral π-conjugated liquid crystals, have been developed for their unique photofunctions. One of the typical photofunctions is the bulk photovoltaic effect of ferroelectric π-conjugated liquid crystals, which integrates a polar environment based on molecular chirality with an extended π-conjuga...
Preprint
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The arrangement of nanoscale building blocks into patterns with microscale periodicity is challenging to achieve via self-assembly processes. Here, we report on the phase transition-driven collective assembly of gold nanoparticles in a thermotropic liquid crystal. A temperature-induced transition from the isotropic to the nematic phase leads to the...
Article
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We report a label-free method for detection of the SARS-CoV-2 virus in nasopharyngeal swab samples without purification steps and multiplication of the target which simplifies and expedites the analysis process. The kit consists of a textile grid on which liquid crystals (LC) are deposited and the grid is placed in a crossed polarized microscopy. T...
Article
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The report shows the temperature behavior of the real part of dielectric permittivity in the static (dielectric constant) and low-frequency (LF) domains in bulk samples of 11CB and its BaTiO 3 -based nanocolloids. The study covers the isotropic liquid (I), nematic (N), smectic A (SmA), and solid crystal (Cr) phases. For each phase, the dominance of...
Article
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The UV intensity during photopolymerization allows control over the structural color of a cholesteric liquid crystal (CLC) polymer photonic coating in a single step. Simultaneously, the glass transition temperature (Tg) of the polymer can be tuned by the applied UV intensity. Most likely the low intensity photopolymerization increases the inhibitio...
Article
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Liquid crystal elastomers that offer exceptional load-deformation response at low frequencies often require consideration of the mechanical anisotropy only along the two symmetry directions. However, emerging applications operating at high frequencies require all five true elastic constants. Here, we utilize Brillouin light spectroscopy to obtain t...
Chapter
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The flexibility, durability, and lightweight offered by plastic displays have not been accomplished commercially, despite years of research. However, significant commercial progress of a bistable nematic liquid crystal display (LCD) did not occur until the invention of the Zenithal Bistable Display (ZBD) in 1995. Thermotropic liquid crystal behavio...
Preprint
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Liquid crystals are assemblies of rod-like molecules which self-organize to form mesophases, in-between ordinary liquids and anisotropic crystals. At each point, the molecules collectively orient themselves along a privileged direction, which locally defines an orientational order. Sometimes, this order is broken and singularities appear in the for...
Preprint
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Dielectric tensor tomography (DTT) enables the reconstruction of three-dimensional (3D) dielectric tensors, which provides a physical measure of 3D optical anisotropy. Herein, we present a cost-effective and robust method for DTT measurement using a multiplexing approach. By exploiting two orthogonally polarized reference beams with different angle...
Article
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The report elucidates for the first time a significant effect of a strong magnetic field combined with thermal treatment on the texture of thin liquid-crystalline films in a smectic state. The metastable texture generated in the magnetic field was arrested via the crystallization of mesogens while they cooled to room temperature. The effect was dem...