Magnetic field-induced vortex triplet and vortex lattice in a liquid crystal cell

Calisto, Enrique; Clerc, Marcel G.; Zambra, Valeska

doi:10.1103/physrevresearch.2.042026

Cited by 7 publications

(5 citation statements)

References 28 publications

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“…3c. For very low frequencies a vortices lattice is observed 13 . On the other hand, for a given frequency if a high enough voltage is applied, the vortex triplet becomes unstable.…”

Section: Experimental Observationsmentioning

confidence: 99%

“…Considering an homeotropic nematic liquid crystal cell (NLC) with a negative anisotropic dielectric constant, the application of a sufficiently large transverse electric field generates a molecular reorientation on the liquid crystal, resulting in the spontaneous emergence of vortices in the system. Additionally, if one considers a magnetic ring above the cell, the magnetic field structure induce a topological charge in the system, leading to the formation of a vortex triplet 13 with topological charge different fo zero. This vortex triplet is useful to study the dynamics of vortices in nematic liquid crystals.…”

Section: Introductionmentioning

confidence: 99%

“…(c) Phase diagram of the system, which shows the region of parameters asociated to the experiment. For very low frequencies a vortices lattice is observed13 . On the other hand, for a given frequency if a high enough voltage is applied, the vortex triplet becomes unstable.…”

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confidence: 99%

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Topological transition to a vortices lattice in a nematic liquid crystal cell

Gajardo,

Clerc

2023

Liquid Crystals XXVII

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By the application of electromagnetic fields onto an homeotropic nematic liquid crystal cell it is possible to induce vortices, which are particle-type defects with topological charge. The dynamics of the vortices is such that topological charge of the system is conserved, so these defects are always induced in pairs that annihilate after a short amount of time. Using a magnetic ring it is possible to induce a stable vortex triplet that allows the study of its dynamics, which is of an oscillatory kind when a low-frequency voltage is applied. Experimentally, we determine the region of parameters where the vortex triplet is stable, unstable, or becomes a lattice of vortices. We propose an amplitude equation which allow us to describe the vortex dynamics, and numerical simulations show agreement with experimental observations.

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“…3c. For very low frequencies a vortices lattice is observed 13 . On the other hand, for a given frequency if a high enough voltage is applied, the vortex triplet becomes unstable.…”

Section: Experimental Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Topological transition to a vortices lattice in a nematic liquid crystal cell

Gajardo,

Clerc

2023

Liquid Crystals XXVII

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“…These include active motion of topological defects in LC media, [20] decomposition of center and saddle point disclinations, [21,22] ionically charged comet orbit and saddle point disclinations in nematic LCs, [23] skyrmions, [24] motile solitons, [25] and vortex lattices. [26] One example of topological defects, in nematic LCs, is the occurrence of horizontal domains. This was first observed in 1961 by Zvereva and Kapustin then studied in depth by Williams in 1963.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Vertically Stacked Soliton‐Like Domain Walls in Nematic Liquid Crystals

Jones

Melnyk

Macêdo

et al. 2021

Advcd Theory and Sims

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In the standard liquid crystal (LC) geometry, one generally finds a quasi‐parabolic director profile in the vertical direction, where the directors are aligned with an applied field in the center of the cell. In contrast, using a numerical energy minimization approach, we find that there are multiple metastable solutions where the director profile is oscillatory. At low voltages, we find small oscillations, which evolve into standard soliton‐like domain walls as the applied voltage is increased. We predict the thickness of the domain wall with a simple analytic model that gives a good comparison to our numerical calculations, in the standard domain wall regime. For dual‐frequency nematic LCs, the occurrence of this regime can be tuned by a change of the biasing frequency. Moreover, we investigate how domain walls can affect the optical properties of LC‐based devices. For instance, we find that the transmittance curve shifts to higher voltages as domain walls are introduced. This shift can be used to create an efficient tunable filter.

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Vortices nucleation by inherent fluctuations in nematic liquid crystal cells

2022

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Multistable systems are characterized by exhibiting domain coexistence, where each domain accounts for the different equilibrium states. In case these systems are described by vectorial fields, domains can be connected through topological defects. Vortices are one of the most frequent and studied topological defect points. Optical vortices are equally relevant for their fundamental features as beams with topological features and their applications in image processing, telecommunications, optical tweezers, and quantum information. A natural source of optical vortices is the interaction of light beams with matter vortices in liquid crystal cells. The rhythms that govern the emergence of matter vortices due to fluctuations are not established. Here, we investigate the nucleation mechanisms of the matter vortices in liquid crystal cells and establish statistical laws that govern them. Based on a stochastic amplitude equation, the law for the number of nucleated vortices as a function of anisotropy, voltage, and noise level intensity is set. Experimental observations in a nematic liquid crystal cell with homeotropic anchoring and a negative anisotropic dielectric constant under the influence of a transversal electric field show a qualitative agreement with the theoretical findings.

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Magnetic field-induced vortex triplet and vortex lattice in a liquid crystal cell

Cited by 7 publications

References 28 publications

Topological transition to a vortices lattice in a nematic liquid crystal cell

Topological transition to a vortices lattice in a nematic liquid crystal cell

Vertically Stacked Soliton‐Like Domain Walls in Nematic Liquid Crystals

Vortices nucleation by inherent fluctuations in nematic liquid crystal cells

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