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Splay-bend elastic inequalities shape tactoids, toroids, umbilics, and conic section walls in paraelectric, twist-bend, and ferroelectric nematics Liq. Cryst. Rev. (IF 5.1) Pub Date : 2024-03-13 Oleg D. Lavrentovich
Elastic constants of splay K11, twist K22, and bend K33 of nematic liquid crystals are often assumed to be equal to each other in order to simplify the theoretical description of complex director f...
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Preface Liq. Cryst. Rev. (IF 5.1) Pub Date : 2023-04-06 Corrie T. Imrie, Randall D. Kamien, Oleg D. Lavrentovich
Published in Liquid Crystals Reviews (Vol. 10, No. 1-2, 2022)
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Imperfect defects in smectics A Liq. Cryst. Rev. (IF 5.1) Pub Date : 2023-02-15 Yuriy A. Nastishin, Claire Meyer
In real samples, focal conic domains (FCDs) and double helical domains (DHDs) in smectic A phases are frequently distorted. Distortions show up as imperfections of conjugated disclinations. These a...
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Geometric theory of topological defects: methodological developments and new trends Liq. Cryst. Rev. (IF 5.1) Pub Date : 2023-02-06 Sébastien Fumeron, Bertrand Berche, Fernando Moraes
ABSTRACT Liquid crystals generally support orientational singularities of the director field known as topological defects. These latter modify transport properties in their vicinity as if the geometry was non-Euclidean. We present a state-of-the-art of differential geometry of nematic liquid crystals, with a special emphasis on linear defects. We then discuss unexpected but deep connections with cosmology
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Les vertus des défauts: The scientific works of the late Mr Maurice Kleman analysed, discussed and placed in historical context, with particular stress on dislocation, disclination and other manner of local material disbehaviour Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-10-13 Timothy J. Sluckin
In memory of Maurice Kleman: Over the last half century, Maurice Kleman was the High Priest of the science of defects in condensed matter. I discuss some aspects of the history of dislocations, dis...
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One-dimensional patterns and topological defects in smectic liquid crystal films Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-07-20 Bruno Zappone, Emmanuelle Lacaze
Smectic liquid crystals exhibit a remarkable ability to self-organize into a variety of textures, patterns, and arrays extending over large surface areas with microscale periodicity. These structur...
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Defects in bent-core liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-06-26 Antal Jákli, Yuriy Nastishin, Oleg D. Lavrentovich
Topological defects and defect phases of rigid and flexibly bent-shaped liquid crystals are reviewed with emphasis on how they are affected by the departure of molecular shapes from a simple rod. T...
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Exotic structures of a thin film of chiral liquid crystals: a numerical study based on the Landau–de Gennes theory Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-06-26 Jun-ichi Fukuda
Chiral liquid crystals exhibit various intriguing ordered structures arising from helical distortions of the orientational order allowed by chirality. We present our numerical studies on such exoti...
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Entanglements and Whitehead products: generalizing Kleman's construction to higher-dimensional defects Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-05-18 Gareth P. Alexander, Randall D. Kamien
We review the interpretation of Whitehead products in homotopy theory as an entanglement of topological defects in ordered media.
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Liquid crystals as signal transducers for sensing of analytes using aptamer as a recognition probe Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-05-10 Manisha Devi, Ipsita Pani, Santanu Kumar Pal
ABSTRACT The long-range orientational order of liquid crystals (LCs) makes them excellent responsive materials for amplification and transduction of various biochemical events occurring at their interfaces. LC interfaces have been vastly explored for sensing of various macromolecules such as endotoxin, proteins, and disease markers. LC-based sensors possess several advantages over conventional methods
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Manipulation of mechanically nanopatterned line defect assemblies in plane-parallel nematic liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-03-03 Saša Harkai, George Cordoyiannis, Adam L. Susser, Bryce S. Murray, Andrew J. Ferris, Brigita Rožič, Zdravko Kutnjak, Charles Rosenblatt, Samo Kralj
Topological line defects are ubiquitous in nature and appear at all physical scales, including in condensed matter systems, nuclear physics, and cosmology. Particularly useful systems to study line...
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Hopfions, heliknotons, skyrmions, torons and both abelian and nonabelian vortices in chiral liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-03-03 Jin-Sheng Wu, Ivan I. Smalyukh
Widely known for their uses in displays and electro-optics, liquid crystals are more than just technological marvels. They vividly reveal the topology and structure of various solitonic and singula...
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Cholesteric dislocations in mica wedges Liq. Cryst. Rev. (IF 5.1) Pub Date : 2022-03-03 P. Pieranski
A large part of the scientific legacy of Maurice Kleman concerns topological defects in liquid crystals. Here, we focus on the very first article of Kleman on liquid crystals coauthored with Jacque...
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Recent progress at the interface between nanomaterial chirality and liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2021-07-08 Diana P. N. Gonçalves, Marianne E. Prévôt, Şenay Üstünel, Timothy Ogolla, Ahlam Nemati, Sasan Shadpour, Torsten Hegmann
Chirality of nanomaterials is a rapidly evolving field, largely driven by the unique optical, electronic, magnetic or catalytic properties of plasmonic, magnetic and semiconductor nanomaterials among others. Liquid crystals continue to play a major role in developing a better understanding of their inherent chiroptical properties as well as serving as reporters to quantify and visualize nanomaterial
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Liquid crystal technology for vergence-accommodation conflicts in augmented reality and virtual reality systems: a review Liq. Cryst. Rev. (IF 5.1) Pub Date : 2021-07-08 Yu-Jen Wang, Yi-Hsin Lin
With the help of augmented reality (AR) and virtual reality (VR) systems, users can receive information and connect with each other via near-eye displays (NEDs). However, several challenges need to be addressed, and the optics are the major bottlenecks. Users wearing current NEDs typically suffer from vergence-accommodation conflict (VAC). Furthermore, people with refractive errors need a pair of prescription
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Design of nematic liquid crystals to control microscale dynamics Liq. Cryst. Rev. (IF 5.1) Pub Date : 2021-05-26 Oleg D. Lavrentovich
ABSTRACT Dynamics of small particles, both living and inanimate, has fascinated scientists for centuries. Learning how to control it could open technological opportunities in the transformation of stored or environmental energy into systematic motion. This review presents an approach to command microscale dynamics by using liquid crystals as an environment and liquid crystal elastomers as substrates
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Effect of phase transitions on liquid crystal colloids: a short review Liq. Cryst. Rev. (IF 5.1) Pub Date : 2021-04-02 Kottoli Poyil Zuhail, Matjaž Humar, Surajit Dhara
We present a brief review on the effect of phase transitions on liquid crystal colloids. The paper focuses on the evolution of dipolar, quadrupolar and boojum colloids and the ensuing elastic distortions of the director field across phase transitions between various phases, including N, SmA, SmC and N*. The role of pre-transitional and post-transitional elasticity on the resulting defect structure
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Effects of photoswitching in complex partially ordered systems Liq. Cryst. Rev. (IF 5.1) Pub Date : 2021-02-11 A. Eremin
In recent years, progress in optics and photonics stimulated the rapid development of multifunctional photoswitchable materials. The ability to manipulate the mechanical, optical and electronic properties of such materials is of paramount interest for emergent technologies. Combination of liquid crystalline order and photoresponsive properties of the mesogens gave rise to the development of photochromic
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Heterodimeric hydrogen-bonded mesogens comprising pyridine moiety: a review Liq. Cryst. Rev. (IF 5.1) Pub Date : 2020-09-12 Deepak Devadiga, T. N. Ahipa
Hydrogen bonding plays an important role in building the super-structures in chemical and biological systems because of its specificity and directionality. In this context, significant works have been conducted recently to study the role of hydrogen bonding interactions in the formation and/or stabilization of mesophases. Also, this flexible and active non-covalent interaction has been widely utilized
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Heterodimeric Hydrogen Bonded Mesogens Comprising Pyridine Moiety: A Review Liq. Cryst. Rev. (IF 5.1) Pub Date : 2020-08-28 Deepak Devadiga, T.N. Ahipa
Hydrogen bonding plays an important role in building the super-structures in chemical and biological systems because of its specificity and directionality. In this context, significant works have been conducted recently to study the role of hydrogen bonding interactions in the formation and/or stabilization of mesophases. Also, this flexible and active non-covalent interaction has been widely utilized
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Memoirs of my time at Kent State University during formation of the Liquid Crystal Institute Liq. Cryst. Rev. (IF 5.1) Pub Date : 2020-03-04 Leslie Gulrich
(2020). Memoirs of my time at Kent State University during formation of the Liquid Crystal Institute. Liquid Crystals Reviews: Vol. 8, No. 1, pp. 1-4.
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Lipid-based Liquid Crystalline Films and Solutions for the Delivery of Cargo to Cells. Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-11-04 Marilyn Porras-Gomez,Cecilia Leal
A major challenge in the delivery of cargo (genes and/or drugs) to cells using nanostructured vehicles is the ability to safely penetrate plasma membranes by escaping the endosome before degradation, later releasing the payload into the cytoplasm or organelle of interest. Lipids are a class of bio-compatible molecules that self-assemble into a variety of liquid crystalline constructs. Most of these
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Lehmann effect in nematic and cholesteric liquid crystals: a review Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-10-17 P. Oswald, A. Dequidt, G. Poy
(2019). Lehmann effect in nematic and cholesteric liquid crystals: a review. Liquid Crystals Reviews: Vol. 7, No. 2, pp. 142-166.
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Recent advancements in the mesogens comprising of 1,3,5-triazine core moiety Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-09-23 Deepak Devadiga, T. N. Ahipa
Research works on new discoid molecules, comprehending an aromatic/heteroaromatic rigid core with flexible peripheral chains, have been gathered with the multiplying attentiveness due to their prime importance as prototype systems for the charge and energy transport investigation and owing to the prospect of their organo-electronic applications. This critical review article delineates the recent headway
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The role of hydrogen bonds in the mesomorphic behaviour of supramolecular assemblies organized in dendritic architectures Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-05-29 Michael Arkas, I. Kitsou, A. Gkouma, M. Papageorgiou
Dendritic polymers are artificial compounds with a unique, repeatedly branched structure inspired by the respective patterns, encountered in trees. They are recognized as the fourth major macromolecular architectural class next to linear, cross linked and branched polymers. Regarding the formation of liquid crystalline phases, they follow the same rules as all the other categories. Suitable chemical
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Tailoring surface patterns to direct the assembly of liquid crystalline materials Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-04-08 Yu Xia, Apiradee Honglawan, Shu Yang
Molecular ordering and the defect structures of a material play essential roles in its function and performance. Controlling molecular alignment and topological defects has been a cornerstone in the field of liquid crystalline (LC) materials. Here, we present an overview of different methods to tailor surface chemistry and surface topography in order to direct the assemblies of LCs, leading to complex
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Interaction and self-organization of inclusions in two-dimensional free-standing smectic films Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-04-05 P. V. Dolganov, P. Cluzeau, V. K. Dolganov
In this article we review interactions and collective behavior of inclusions in free-standing smectic films with in-plane orientational ordering. The inclusions interact on large distances and can form various self-organised structures. Topological defects of the director field play a key role in self-organization. Various types of interaction are realized, including dipolar, quadrupolar and interactions
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Nematicons: reorientational solitons from optics to photonics Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-04-03 Gaetano Assanto
The most recent advances on phenomena and effects which involve spatial optical solitons stemming from the reorientational optical response of nematic liquid crystals, the so called Nematicons, are reviewed hereby. After the initial assessment and basic understanding, in the past few years, significant progress on nematicon optics has included cavity-less beam bistability and hysteresis, spontaneous
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Ferroelectric liquid crystal nanocomposites: recent development and future perspective Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-03-22 Satya Prakash Yadav, Kanchan Yadav, Jayeeta Lahiri, Avanish Singh Parmar
In recent years, dispersion of nanomaterials in liquid crystal media has attracted a great deal of attention for their applications in various fields and basic understanding. In this regard, nanocomposites of ferroelectric liquid crystals hold a great promise for technological advancement in displays, sensors, development of hybrid materials for optical applications and others. With the emphasis on
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Interpretation of saddle-splay and the Oseen-Frank free energy in liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2019-03-01 Jonathan V. Selinger
This article re-examines a classic question in liquid-crystal physics: What are the elastic modes of a nematic liquid crystal? The analysis uses a recent mathematical construction, which breaks the director gradient tensor into four distinct types of mathematical objects, representing splay, twist, bend, and a fourth deformation mode. With this construction, the Oseen-Frank free energy can be written
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Pierre-Gilles de Gennes and physics of liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2018-11-08 Andrei A. Sonin
A contribution of the well-known physicist-theoretician, the Nobel prize laureate P.-G. de Gennes to the liquid crystal research is analyzed. A history of creation by de Gennes of the so-called Orsay liquid crystal group is also described and a brief scientist’s biography is given.
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Liquid crystal elastomers: an introduction and review of emerging technologies Liq. Cryst. Rev. (IF 5.1) Pub Date : 2018-10-10 Sabina W. Ula, Nicholas A. Traugutt, Ross H. Volpe, Ravi R. Patel, Kai Yu, Christopher M. Yakacki
Liquid crystal elastomers (LCEs) are a unique class of materials that combine rubber elasticity with liquid crystalline anisotropy to produce exceptional physical and optical properties such as actuation, soft elasticity, and birefringence. This review gives a brief overview of the physics behind liquid crystals and classifications of LCEs before discussing the methods traditionally used to synthesize
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Cholesteric and blue-phase liquid photonic crystals for nonlinear optics and ultrafast laser pulse modulations Liq. Cryst. Rev. (IF 5.1) Pub Date : 2018-08-22 Iam Choon Khoo
We present a comprehensive review of nonlinear optics and photonics of two ordered phases of liquid crystals, namely, Cholesteric and Blue-phase liquid crystals that exhibit 1- and 3-D photonic crystalline properties. We delve into the ultrafast individual molecular electronic nonlinearity as well as crystalline non-electronic nonlinearities arising from laser induced electrostriction, thermal-, density-
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Liquid crystals for signal processing applications in the microwave and millimeter wave frequency ranges Liq. Cryst. Rev. (IF 5.1) Pub Date : 2018-08-19 Robert Camley, Zbigniew Celinski, Yuriy Garbovskiy, Anatoliy Glushchenko
Liquid crystal technology has a long well-established history of applications in visible light, primarily in the display industry. In contrast, applications at lower frequencies (microwave through infrared) are less common. In this paper, we examine non-display applications and review the use of liquid crystal materials for tunable signal processing devices operating at microwave and millimeter wave
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Liquid crystal light valves as optically addressed liquid crystal spatial light modulators: optical wave mixing and sensing applications Liq. Cryst. Rev. (IF 5.1) Pub Date : 2018-07-21 S. Residori, U. Bortolozzo, J. P. Huignard
Liquid crystals offer an unique versatile platform for optical applications and light manipulation. Indeed, besides the well-known realization of liquid crystal displays, liquid crystal-based technologies and, particularly, spatial light modulators (SLM) allow achieving efficient control of the phase and amplitude of optical beams at various wavelengths and optical powers. Thanks to their transparency
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Liquid crystal lenses with tunable focal length Liq. Cryst. Rev. (IF 5.1) Pub Date : 2018-03-01 Yi-Hsin Lin, Yu-Jen Wang, Victor Reshetnyak
Lenses with tunable focal length play important roles in nature by helping species avoid predators and capture prey. Many practical devices mimic lens concept for imaging, sensing, and detection. This review covers fundamental optics of lenses and its extension to lenses made of liquid crystals (LCs). Three main types of LC lenses are described, namely, lenses with curved surfaces, flat gradient-index
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Cellulosic liquid crystals for films and fibers Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-10-29 J. P. Canejo, N. Monge, C. Echeverria, S. N. Fernandes, M. H. Godinho
Cellulose, the most abundant natural polymer on earth, is used in numerous applications in our day-to-day life. However, the discovery that cellulose-based systems could lead to the formation of liquid crystalline phases only dates to the 1970s. Compared with all known applications of cellulose, the liquid crystalline behavior has been less considered. Associated with this are the low solubility of
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Liquid crystal nanoparticles for commercial drug delivery Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-08-17 J. Mo, G. Milleret, M. Nagaraj
Liquid crystals (LCs) are an intermediate state of matter that exists between conventional solids and liquids. They are vital to the existence of life as several critical components in living organisms such as cell wall and biochemical fluids are liquid crystalline in nature. Drug delivery based on LCs is a vast field of research. In recent years there has been a huge leap in interest into using LCs
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Refraction of light on flat boundary of liquid crystals or anisotropic metamaterials Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-07-04 A. Bregar, T. J. White, M. Ravnik
Refraction of light at a boundary between an isotropic dielectric and an optically anisotropic material – liquid crystalline or metamaterial – is elaborated, especially the dependence on the angle between the anisotropic material birefringence optical axis and the material surface. Different regimes of negative and positive refraction are shown, caused by the liquid-crystalline optical response or
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Self-assembly and polymer-stabilization of lyotropic liquid crystals in aqueous and non-aqueous solutions Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-05-19 Dae-Yoon Kim, Seok-In Lim, Daseal Jung, Joo-Kyoung Hwang, Namil Kim, Kwang-Un Jeong
With growth of interest in functional materials possessing highly organized and well-defined nanostructures, lyotropic mesophases have received much attention. Amphiphiles and chromogens can spontaneously construct ordered lyotropic liquid crystal (LLC) and lyotropic chromonic liquid crystal phases in both organic and inorganic solvents. The combined properties of self-organization with facile orientation
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Ferromagnetic nematic liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-04-01 Alenka Mertelj, Darja Lisjak
This review presents experimental realization and behaviour of the ferromagnetic nematic phase, which is observed in different suspensions of magnetic nanoplatelets. After a general introduction, the challenges in the synthesis of magnetic nanoplatelets and preparation of the nematic suspensions are discussed. A brief explanation of a simple macroscopic theory, which can be used to understand the main
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Editorial Board Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-03-17
(2016). Editorial Board. Liquid Crystals Reviews: Vol. 4, No. 2, pp. ebi-ebi.
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From flow birefringence in the isotropic phase of liquid crystals to the identification of shear elasticity in liquids Liq. Cryst. Rev. (IF 5.1) Pub Date : 2017-02-09 P. Kahl, L. Noirez
Recent experimental developments show that without reticulation links or entanglements, the isotropic phase of liquid crystals can work mechanically as an elastomer and optically as a harmonic oscillator at the sub-millimetre scale. The strength of the elastic response depends on the molecular architecture and is enhanced when the liquid-crystal molecules are attached as side-chain moieties to a chain
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Electrically induced patterns in nematics and how to avoid them Liq. Cryst. Rev. (IF 5.1) Pub Date : 2016-10-31 N. Éber, P. Salamon, Á. Buka
Electric field-induced patterns in liquid crystals have been observed and studied for about 50 years. During this time, a great variety of structures, detected under different conditions, have been described; theoretical descriptions were also developed parallel with the experiments and a huge number of papers have been published. The non-vanishing interest in the topic is due to several factors. First
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Holographic display and storage based on photo-responsive liquid crystals Liq. Cryst. Rev. (IF 5.1) Pub Date : 2016-10-18 Pengcheng Zhou, Yan Li, Xiao Li, Shuxin Liu, Yikai Su
Liquid crystals (LCs) are widely used in nonlinear optics because of their sensitive responses to optical stimulation. Combined with other optoelectronic materials such as azo dyes, quantum dots (QDs), etc., LCs show very large optical nonlinearity which makes them suitable for applications in optical information processing, including holographic display and holographic storage. In this review, we
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Cholesteric solid spherical microparticles: chiral optomechanics and microphotonics Liq. Cryst. Rev. (IF 5.1) Pub Date : 2016-07-21 R. J. Hernández, C. Provenzano, A. Mazzulla, P. Pagliusi, M. Viola, G. Cipparrone
This article reviews the main results from the investigations performed on solid chiral microparticles based on polymerized cholesteric droplets. The procedures of particles generation, the structural characterization, optomechanics and microphotonics investigations are shown. The aim of this work is to give a picture of the innovation introduced by exploring the combination of chirality, self-organization
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Biaxial nematic liquid crystals – theory, simulation and experiment Liq. Cryst. Rev. (IF 5.1) Pub Date : 2016-07-21 Antal Jákli
(2016). Biaxial nematic liquid crystals – theory, simulation and experiment. Liquid Crystals Reviews: Vol. 4, No. 1, pp. 80-81.
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Defect structures in nematic liquid crystal shells of different shapes Liq. Cryst. Rev. (IF 5.1) Pub Date : 2016-06-07 L. V. Mirantsev, E. J. L. de Oliveira, I. N. de Oliveira, M. L. Lyra
The present review is devoted to recent studies of structures with topological defects on nematic liquid crystal (NLC) shells of different shapes and to the possibility of using external electric fields to manipulate these structures. It is shown that principal curvatures of bounding surfaces have a strong effect on the number and arrangement of these defects on NLC shells. It is also shown that external
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Liquid-crystal micro-photonics Liq. Cryst. Rev. (IF 5.1) Pub Date : 2016-03-21 Igor Muševič
This review presents the main results that were achieved over the past decade in the new field of liquid-crystal micro-photonics. After a general introduction to some aspects of state-of-the-art micro-photonics technologies, nematic colloids are discussed in terms of their self-assembly and photonic properties. Liquid-crystal lasers, based on spatially periodic, liquid-crystal phases, are reviewed