scholarly journals Mechanical analogies for nonlinear light beams in nonlocal nematic liquid crystals

2018 ◽  
Vol 27 (04) ◽  
pp. 1850046 ◽  
Author(s):  
Gaetano Assanto ◽  
Panayotis Panayotaros ◽  
Noel F. Smyth
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Type Equation ◽  
Beam Propagation ◽  
Dimensional System ◽  
Dynamical Equations ◽  
Approximate Methods ◽  
Existence And Stability ◽  
Nonlinear Features ◽  
Light Beams

The equations governing nonlinear light beam propagation in nematic liquid crystals form a [Formula: see text]-dimensional system consisting of a nonlinear Schrödinger-type equation for the electric field of the wavepacket and an elliptic equation for the reorientational response of the medium. The latter is “nonlocal” in the sense that it is much wider than the size of the beam. Due to these nonlocal, nonlinear features, there are no known general solutions of the nematic equations; hence, approximate methods have been found convenient to analyze nonlinear beam propagation in such media, particularly the approximation of solitary waves as mechanical particles moving in a potential. We review the use of dynamical equations to analyze solitary wave propagation in nematic liquid crystals through a number of examples involving their trajectory control, including comparisons with experimental results from the literature. Finally, we make a few general remarks on the existence and stability of optically self-localized solutions of the nematic equations.

scholarly journals REFRACTION OF NONLINEAR LIGHT BEAMS IN NEMATIC LIQUID CRYSTALS

2012 ◽  
Vol 21 (03) ◽  
pp. 1250033 ◽  
Author(s):  
GAETANO ASSANTO ◽  
NOEL F. SMYTH ◽  
WENJUN XIA
Keyword(s):  
Steady State ◽  
Liquid Crystals ◽  
Solitary Waves ◽  
Nematic Liquid Crystals ◽  
Optical Solitons ◽  
Numerical Results ◽  
Dielectric Interface ◽  
Modulation Theory ◽  
Light Beams

We use modulation theory to analyze the interaction of optical solitons and vortices with a dielectric interface between two regions of nematic liquid crystals. In the analysis we consider the role of nonlocality, anisotropy and nonlinear reorientation and compare modulation theory results with numerical results. Upon interacting with the interface, nematicons undergo transverse distortion but remain stable and eventually return to a steady state, whereas vortices experience an enhanced instability and can break up into bright beams or solitary waves.

scholarly journals Possibility of discrete beam propagation in chiral nematic liquid crystals

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
MichaĹ‚ KwaĹ›ny ◽  
Urszula A. Laudyn ◽  
PaweĹ‚ Jung ◽  
Mirosław A. Karpierz
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Beam Propagation ◽  
Chiral Nematic

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

Laser Beam Induces Reorientation in Nematic Liquid Crystals

2010 ◽  
Vol 428-429 ◽  
pp. 224-227
Author(s):  
I Min Jiang ◽  
Yu Jen Chen ◽  
Wen Chi Hung ◽  
C.T. Kuo ◽  
D.J. Jang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Laser Beam ◽  
Nematic Liquid Crystals ◽  
Beam Propagation ◽  
Isotropic Phase ◽  
Optical Alignment ◽  
Optically Induced

Nematic liquid crystals (NLCs) can be easily reoriented by the laser beam at the temperature closed to the nematic–isotropic phase transition (TNI). At the temperature closed to TNI, the propagating mode of laser beam and the optically induced phase transition were explored by using a microscopic conoscope technique. This investigation demonstrates the formation of soliton at particular beam propagation modes. The interaction between nematic liquid crystals and the laser beam with different polarizations showed the nonlinearity in optical alignment.

scholarly journals Existence and Stability of Kayaking Orbits for Nematic Liquid Crystals in Simple Shear Flow

2021 ◽  
Author(s):  
David Chillingworth ◽  
M. Gregory Forest ◽  
Reiner Lauterbach ◽  
Claudia Wulff
Keyword(s):  
Liquid Crystals ◽  
Shear Flow ◽  
Nematic Liquid Crystals ◽  
Perturbation Parameter ◽  
Rotation Group ◽  
Simple Shear Flow ◽  
Periodic Rotation ◽  
Steady Shear Flow ◽  
Existence And Stability ◽  
Equivariant Dynamical Systems

AbstractWe use geometric methods of equivariant dynamical systems to address a long-standing open problem in the theory of nematic liquid crystals, namely a proof of the existence and asymptotic stability of kayaking periodic orbits in response to steady shear flow. These are orbits for which the principal axis of orientation of the molecular field (the director) rotates out of the plane of shear and around the vorticity axis. With a small parameter attached to the symmetric part of the velocity gradient, the problem can be viewed as a symmetry-breaking bifurcation from an orbit of the rotation group $$\mathrm{SO}(3)$$ SO ( 3 ) that contains both logrolling (equilibrium) and tumbling (periodic rotation of the director within the plane of shear) regimes as well as a continuum of neutrally stable kayaking orbits. The results turn out to require expansion to second order in the perturbation parameter.

DISSIPATIVE SELF-CONFINED OPTICAL BEAMS IN DOPED NEMATIC LIQUID CRYSTALS

2007 ◽  
Vol 16 (03) ◽  
pp. 295-305 ◽  
Author(s):  
ALESSANDRO ALBERUCCI ◽  
GAETANO ASSANTO
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Optical Gain ◽  
Beam Propagation ◽  
Optical Amplification ◽  
Nonlinear Beam ◽  
Light Localization ◽  
Non Local ◽  
Optical Beams

We study light localization in nonlinear non-local nematic liquid crystals capable of optical gain. We address the role of optical amplification on nonlinear beam propagation, considering various forms of gain and configurations.

scholarly journals Beam Propagation in Nematic Liquid Crystals

2007 ◽  
Vol 112 (5) ◽  
pp. 877-883 ◽  
Author(s):  
A.I. Strinic ◽  
M.R. Belic
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Beam Propagation
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