scholarly journals Elastic director vibrations in nematic liquid crystals

2014 ◽  
Vol 26 (1) ◽  
pp. 93-107 ◽  
Author(s):  
STEFANO S. TURZI
Keyword(s):  
Wave Propagation ◽  
Liquid Crystals ◽  
Sound Wave ◽  
Soft Matter ◽  
Nematic Liquid Crystals ◽  
Molecular Relaxation ◽  
Molecular Distribution ◽  
Nematic Elastomers ◽  
Small Anisotropy

Recently Biscari, DiCarlo and Turzi [Anisotropic wave propagation in nematic liquid crystals, Soft Matter 10, 8296–8307.] proposed a theory for nematoacustics which models nematic liquid crystals as nematic elastomers with molecular relaxation. Here, we extend the analysis of this theory to account for the director motion possibly induced by the propagation of a sound wave. We find that the director vibration is related to the - usually small - anisotropy of the molecular distribution, thus providing a justification to the relative high ultrasonic intensities required to observe non-negligible acousto-optic responses.

scholarly journals Emergence and stabilization of transient twisted defect structures in confined achiral liquid crystals at a phase transition.

Soft Matter ◽  
2021 ◽  
Author(s):  
Jose X Velez ◽  
Zhaofei Zheng ◽  
Daniel A. Beller ◽  
Francesca Serra
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Soft Matter ◽  
Capillary Tube ◽  
Nematic Liquid Crystals ◽  
Defect Structures

Spontaneous emergence of chirality is a pervasive theme in soft matter. We report a transient twist forming in achiral nematic liquid crystals confined to a capillary tube with square cross...

scholarly journals Anisotropic wave propagation in nematic liquid crystals

Soft Matter ◽  
2014 ◽  
Vol 10 (41) ◽  
pp. 8296-8307 ◽  
Author(s):  
Paolo Biscari ◽  
Antonio DiCarlo ◽  
Stefano S. Turzi
Keyword(s):  
Wave Propagation ◽  
Liquid Crystals ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals

We show that elastic anisotropy and relaxation are at the origin of the main experimental features of nematoacoustics.

scholarly journals Beam splitting in chiral nematic liquid crystals

2018 ◽  
Vol 10 (4) ◽  
pp. 109
Author(s):  
Filip Sala
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Soft Matter ◽  
Nematic Liquid Crystals ◽  
Beam Propagation Method ◽  
Beam Propagation ◽  
Optical Solitons ◽  
Molecular Reorientation ◽  
Chiral Nematic

By lunching the beam into the chiral nematic liquid crystals it is possible to achieve a non-diffractive beam similar to a soliton. This effect is caused by the molecular reorientation i.e. nonlinear response of the material forming the areas of higher refractive index. Diffraction is suppressed by the focusing effect. For appropriate launching conditions it is also possible to achieve a beam which splits into two or more separate beams. Such phenomenon is discussed in this article and analyzed theoretical. To model this effect Fully Vectorial Beam Propagation Method coupled with the Frank-Oseen elastic theory is used. Simulations are performed for various input beam powers, widths, polarization angles and launching positions. Full Text: PDF ReferencesG. Assanto and M. A. Karpierz, "Nematicons: self-localised beams in nematic liquid crystals", Liq. Cryst. 36, 1161–1172 (2009) CrossRef G. Assanto, Nematicons: Spatial Optical Solitons in Nematic Liquid Crystals, John Wiley & Sons Inc. Hoboken, New Jersey (2013) DirectLink A. Piccardi, A. Alberucci, U. Bortolozzo, S. Residori, and G. Assanto, "Soliton gating and switching in liquid crystal light valve", Appl. Phys. Lett. 96, 071104 (2010). CrossRef D. Melo, I. Fernandes, F. Moraes, S. Fumeron, and E. Pereira, "Thermal diode made by nematic liquid crystal", Phys. Lett. A 380, 3121 – 3127 (2016). CrossRef U. Laudyn, M. Kwaśny, F. A. Sala, M. A. Karpierz, N. F. Smyth, G. Assanto, "Curved optical solitons subject to transverse acceleration in reorientational soft matter", Sci. Rep. 7, 12385 (2017) CrossRef M. Kwaśny, U. A. Laudyn, F. A. Sala, A. Alberucci, M. A. Karpierz, G. Assanto, "Self-guided beams in low-birefringence nematic liquid crystals", Phys. Rev. A 86, 013824 (2012) CrossRef F. A. Sala, M. M. Sala-Tefelska, "Optical steering of mutual capacitance in a nematic liquid crystal cell", J. Opt. Soc. Am. B. 35, 133-139 (2018) CrossRef U. A. Laudyn, A. Piccardi, M. Kwasny, M. A. Karpierz, G. Assanto, "Thermo-optic soliton routing in nematic liquid crystals", Opt. Lett. 43, 2296-2299 (2018) CrossRef F. A. Sala, M. M. Sala-Tefelska, M. J. Bujok, J. "Influence of temperature diffusion on molecular reorientation in nematic liquid crystals", Nonlinear Opt. Phys. Mater. 27, 1850011 (2018) CrossRef I-C Khoo Liquid crystals John Wiley & Sons, Inc (2007) DirectLink P. G. de Gennes, J. Prost, The Physics of Liquid Crystals, Clarendon Press (1995) DirectLink U. A. Laudyn, P. S. Jung, M. A. Karpierz, G. Assanto, "Quasi two-dimensional astigmatic solitons in soft chiral metastructures", Sci. Rep. 6, 22923 (2016) CrossRef J. Beeckman, A. Madani, P. J. M. Vanbrabant, P. Henneaux, S-P. Gorza, M. Haelterman, "Switching and intrinsic position bistability of soliton beams in chiral nematic liquid crystals", Phys. Rev. A 83, 033832 (2011) CrossRef A. Madani, J. Beeckman, K. Neyts, "An experimental observation of a spatial optical soliton beam and self splitting of beam into two soliton beams in chiral nematic liquid crystal", Opt. Commun. 298–299, 222-226, (2013) CrossRef G. D. Ziogos, E. E. Kriezis, "Modeling light propagation in liquid crystal devices with a 3-D full-vector finite-element beam propagation method", Opt. Quant. Electron 40, 10 (2008) CrossRef F. A. Sala, M. A. Karpierz, "Chiral and nonchiral nematic liquid-crystal reorientation induced by inhomogeneous electric fields", J. Opt. Soc. Am. B 29, 1465-1472 (2012) CrossRef F. A. Sala, M. A. Karpierz, "Modeling of molecular reorientation and beam propagation in chiral and non-chiral nematic liquid crystals", Opt. Express 20, 13923-13938 (2012) CrossRef F. A. Sala, "Design of false color palettes for grayscale reproduction", Displays, 46, 9-15 (2017) CrossRef

The Clausius-Mossotti relation for anisotropic molecular fluids

1981 ◽  
Vol 59 (3) ◽  
pp. 375-377 ◽  
Author(s):  
P. Palffy-Muhoray ◽  
D. A. Balzarini
Keyword(s):  
Correlation Function ◽  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Dipole Field ◽  
Anisotropic Fluid ◽  
Particle Correlation ◽  
Molecular Fluids ◽  
Molecular Distribution

It is shown that in the interior of a uniformly polarized homogeneous anisotropic fluid there exists a family of similar surfaces, determined by the two-particle correlation function, having the property that the dipole field at the origin due to molecules within these surfaces is zero. The resulting Clausius–Mossotti relation contains a parameter, ηαβ, which is a measure of the anisotropy of the molecular distribution. These results are applicable to nematic liquid crystals.

Tunable and programmable topological valley transport in photonic crystals with liquid crystals

2022 ◽  
Author(s):  
Yulin Zhao ◽  
Feng Liang ◽  
Xiangru Wang ◽  
Deshuang Zhao ◽  
Bing-Zhong Wang
Keyword(s):  
Wave Propagation ◽  
Liquid Crystals ◽  
Photonic Crystals ◽  
Symmetry Breaking ◽  
Relative Permittivity ◽  
Nematic Liquid Crystals ◽  
Inversion Symmetry ◽  
Edge States ◽  
Beam Splitting ◽  
Topological Transition

Abstract Topological valley transport in photonic crystals (PCs) has attracted great attention owing to its edge modes immune to backscattering. However, flexibly dynamically controlling and reconfiguring the pathway of the topological one-way propagation is still challenging. Here, we propose a tunable and programmable valley PC structure based on nematic liquid crystals (LCs). Inversion symmetry breaking and topological transition are implemented through controlling the relative permittivity of the LC cells. Topological protection of valley edge states and valley-locked beam splitting are demonstrated. Moreover, the LC-based PC can be discretized to a number of supercells, each of which can be coded with “0” or “1”. The wave propagation pathway can be dynamically reconfigured by programming different coding patterns.

Wave Propagation in Nematic Liquid Crystals

1971 ◽  
Vol 54 (12) ◽  
pp. 5027-5034 ◽  
Author(s):  
James D. Lee ◽  
A. Cemal Eringen
Keyword(s):  
Wave Propagation ◽  
Liquid Crystals ◽  
Nematic Liquid Crystals

Spectroscopic insight into molecular fluctuations and phase stability of nematic composites containing gold nanoparticles or carbon nanotubes

2017 ◽  
Vol 19 (34) ◽  
pp. 23302-23308 ◽  
Author(s):  
Mathias Bourg ◽  
Martin Urbanski
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Liquid Crystals ◽  
Phase Stability ◽  
Nematic Liquid Crystals ◽  
Fundamental Difference ◽  
Molecular Relaxation ◽  
Relaxation Dynamic ◽  
Insight Into

We demonstrate the fundamental difference between molecular dopants and nanoparticles in their impact on the molecular relaxation dynamic of nematic liquid crystals.

Nonlinear Wave Propagation and Spatial Solitons in Nematic Liquid Crystals

2003 ◽  
Vol 12 (02) ◽  
pp. 123-134 ◽  
Author(s):  
Gaetano Assanto ◽  
Marco Peccianti ◽  
Katarzyna A. Brzdakiewicz ◽  
Antonio de Luca ◽  
Caesar Umeton
Keyword(s):  
Wave Propagation ◽  
Liquid Crystals ◽  
Nonlinear Wave ◽  
Nonlinear Response ◽  
Nematic Liquid Crystals ◽  
Weak Signal ◽  
Spatial Solitons ◽  
Nonlinear Wave Propagation ◽  
Soliton Interactions ◽  
Planar Cells

Optical spatial solitons have been demonstrated in bulk nematic liquid crystals. We present an overview of our recent experimental results on nonlinear wave propagation in nematic liquid crystals, focusing on spatial solitons through the reorientational nonlinear response. Various phenomena, including spatial readdressing, weak signal guiding and two-soliton interactions, are observed in voltage biased planar cells.

Sign in / Sign up

Export Citation Format

Share Document