Liquid crystal phases in confined geometries

Liquid crystals (LCs) are omnipresent in living matter, whose chirality is an elegant and distinct feature in certain plant tissues, the cuticles of crabs, beetles, arthropods, and beyond. Taking inspiration from nature, researchers have recently devoted extensive efforts toward developing chiral liquid crystalline materials with self-organized nanostructures and exploring their potential applications in diverse fields ranging from dynamic photonics to energy and safety issues. In this review, an account on the state of the art of emerging chiral liquid crystalline nanostructured materials and their technological applications is provided. First, an overview on the significance of chiral liquid crystalline architectures in various living systems is given. Then, the recent significant progress in different chiral liquid crystalline systems including thermotropic LCs (cholesteric LCs, cubic blue phases, achiral bent-core LCs, etc.) and lyotropic LCs (DNA LCs, nanocellulose LCs, and graphene oxide LCs) is showcased. The review concludes with a perspective on the future scope, opportunities, and challenges in these truly advanced functional soft materials and their promising applications.

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Section: Bent-core Liquid Crystalsmentioning

confidence: 99%

Nature‐Inspired Emerging Chiral Liquid Crystal Nanostructures: From Molecular Self‐Assembly to DNA Mesophase and Nanocolloids

2018

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“…Previous experimental studies of DLCs confined in cylindrical nanopores have revealed a remarkably complex, sometimes very surprising self-assembly behaviour [24,26,[38][39][40][41][42][43]. Experimental studies on HAT6 in AAO indicate that for planar anchoring, i.e., the molecules lie flat on the hydrophilic pore walls, no long-range intercolumnar hexagonal order is detectable for pore diameters d below 20 nm [44].…”

Section: Introductionmentioning

confidence: 99%

Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

et al. 2019

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light the whole structure is described as a metamaterial [1][2][3]. A monolithic membrane traversed by a parallel array of cylindrical nanochannels represents such a metamaterial, see illustration in Fig. 1. The advent of tailorable porosity at the nanoscale and thus of an adjustable "meta-atomic" structure offers new opportunities to tailor the optical anisotropy of such metamaterials. Effective optical properties, not achievable by base materials, are possible [2-8], specifically adjustable birefringence. This is of particular relevance for important polarisation management components, such as waveplates and compensators, that play an essential part in modern optical communication systems [9].A versatile route to fine-tune optics of porous materials is filling the pore space with a liquid crystal (LC) [10,11]. In the bulk case LCs play a dominant role for the manipulation of optical anisotropy [12]. By embedding LCs in nanoporous media the self-assembly and self-healing mechanisms can be used to design a new soft-hard metamaterial. The LC adds optical functionality, whereas the arXiv:1911.10052v1 [cond-mat.soft]

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“…The proposed tuning mechanism is applicable in the mid-infrared regime where the typical size of a PC cell size is of the order of a few micrometers. Reorientation of the LC molecules infiltrating the structures on this scale have been shown to be feasible [53][54][55][56][57]. In the near-infrared regime, effective tuning of the LC might be challenging due to the tight confinement inside of the PC structure [51,[58][59][60][61][62].…”

Section: Resultsmentioning

confidence: 99%

Reconfigurable topological photonic crystal

et al. 2018

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Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (nontrivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.

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Liquid crystal phases in confined geometries

Cited by 40 publications

References 150 publications

Nature‐Inspired Emerging Chiral Liquid Crystal Nanostructures: From Molecular Self‐Assembly to DNA Mesophase and Nanocolloids

Nature‐Inspired Emerging Chiral Liquid Crystal Nanostructures: From Molecular Self‐Assembly to DNA Mesophase and Nanocolloids

Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

Reconfigurable topological photonic crystal

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