Molecular interpretation of the absorption-induced optical reorientation of nematic liquid crystals

Jánossy, I.

doi:10.1103/physreve.49.2957

Cited by 263 publications

(123 citation statements)

References 8 publications

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“…45,[49][50][51][52] To investigate the possible unintended effects due to dye photoexcitation, we measured the FRS rate constant as a function of the pump-beam intensity in the nematic phase at a temperature of 33.9°C with q 2 ϭ2.47 ϫ10 8 cm Ϫ2 . Attenuation of the pump beam by up to a factor of 14 did not result in a measurable change in the FRS rate constants for diffusion parallel or perpendicular to the director, implying that even an order-of-magnitude change in the cis population does not measurably affect our diffusioncoefficient results.…”

Section: Methodsmentioning

confidence: 99%

Forced Rayleigh scattering studies of tracer diffusion in a nematic liquid crystal: The relevance of complementary gratings

Spiegel

Thompson

Campbell

2001

The Journal of Chemical Physics

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We have employed forced Rayleigh scattering ͑FRS͒ to study the diffusion of an azo tracer molecule ͑methyl red͒ through a nematic liquid crystal ͑5CB͒. This system was first investigated in an important study by Hara et al. ͓Jpn. J. Appl. Phys. 23, 1420 ͑1984͔͒. Since that time, it has become clear that the presence of complementary ground-state and photoproduct FRS gratings can result in nonexponential profiles, and that complementary-grating effects are significant even when ''minor'' deviations from exponential decay are observed. We have investigated the methyl red/5CB system in order to evaluate the possible effects of complementary gratings. In the isotropic phase, we find that the presence of complementary gratings results in a nonmonotonic FRS signal, which significantly changes the values inferred for the isotropic diffusion coefficients. As a result, the previously reported discontinuity at the nematic/isotropic transition temperature (T NI ) is not present in the new data. On the other hand, in the nematic phase, the new experiments largely confirm the previous observations of single-exponential FRS decay and the non-Arrhenius temperature dependence of the nematic diffusion coefficients close to T NI . Finally, we have also observed that the decrease in the diffusion anisotropy with increasing temperature can be correlated with the 5CB nematic order parameter S(T) over the full nematic temperature range.

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Section: Methodsmentioning

confidence: 99%

Forced Rayleigh scattering studies of tracer diffusion in a nematic liquid crystal: The relevance of complementary gratings

Spiegel

Thompson

Campbell

2001

The Journal of Chemical Physics

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“…From theoretical curves plotted in figures 5 and 6 approximately 10 mW/µm of light power in a planar mode induces effective index changes of a value ∆n~0.1. This extremely large nonlinearity (by some authors called giant) can be enhanced even by two orders of magnitudes in a presence of dyes in a LC mixture [15]. This effect discovered by Janossy is strongly dependent on the light wavelength (see Fig.…”

Section: Liquid Crystalline Planar Waveguidesmentioning

confidence: 95%

Spatial Solitons in Liquid Crystals

Karpierz

2001

Soliton-Driven Photonics

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Reorientational phenomenon in liquid crystals is unique for nonlinear optics applications. Recently there have been shown that the reorientational nonlinearity in nematic liquid crystals can govern spatial solitons in both waveguide and bulk geometry. Such solitons require a few milliwats of light power and they can be controlled by the state of light polarisation or an external electric field. In this paper, the theoretical analysis and experimental results on optical solitons in nematic liquid crystals due to the reorientational nonlinearity are reviewed. The discussion of their properties is preceded by a brief introduction to nonlinear optics of liquid crystals.

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“…The decrease of the threshold laser power needed to induce the T3-1s with a 1064 nm beam is due to the enhancement of the optical reorientation of n͑r͒ enabled by fullerene doping, similar to that in dyedoped LCs. 12,13 However, these Torons do not reappear after turning off U, in contrast to the ones generated by blue light ͓Figs. 2͑d͒-2͑i͔͒ because, due to the low absorption, infrared beam does not deposit fullerene.…”

mentioning

confidence: 92%

Optically generated adaptive localized structures in confined chiral liquid crystals doped with fullerene

Trushkevych

Ackerman

Crossland

et al. 2010

Applied Physics Letters

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We report the facile optical creation of switchable localized structures in chiral liquid crystals doped with fullerene. In a cholesteric cell unwound by vertical boundary conditions, the initially dispersed fullerenes are deposited from the bulk to the surface of confining glass plates by low-intensity illumination. This alters the surface boundary conditions and allows for the creation of localized particlelike structures with twist-bound defects ͑dubbed Torons͒ that are controlled by electric fields and arranged into patterns of interest for photonic and electro-optic applications.

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Molecular interpretation of the absorption-induced optical reorientation of nematic liquid crystals

Cited by 263 publications

References 8 publications

Forced Rayleigh scattering studies of tracer diffusion in a nematic liquid crystal: The relevance of complementary gratings

Forced Rayleigh scattering studies of tracer diffusion in a nematic liquid crystal: The relevance of complementary gratings

Spatial Solitons in Liquid Crystals

Optically generated adaptive localized structures in confined chiral liquid crystals doped with fullerene

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