Journal ArticleDOI
Transient Electro-Optic Kerr Effect in Liquid Crystalline Isothiocyanates
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TLDR
In this paper, the D.C. Kerr response and the pre-transitional behavior of two liquid crystalline isothiocyanates 4-(4 ′ -n-pentyl phenyl)-phenyl isothIocyanate (5NCS) and 4-( 4 ′ −n-heptylphenyl-phenyl)-isothIOCyanate(7NCS), at temperatures above the smectic-isotropic transition temperatures were investigated.Abstract:
Measurements are reported for the first time on the D.C. Kerr response and the pre-transitional behaviour of two liquid crystalline isothiocyanates 4-(4 ′ -n-pentyl phenyl)-phenyl isothiocyanate (5NCS) and 4-(4 ′ -n-heptyl phenyl)-phenyl isothiocyanate (7NCS) at temperatures above the smectic-isotropic transition temperatures. The Kerr law has been verified and the real part of the third order nonlinear susceptibilities (χ (3) ) above the smectic-isotropic transition are determined for the two liquid crystalline isothiocyanates from the electro-optic Kerr effect (EOKE) experiments. The variation of susceptibility with temperature has also been studied. The results have been compared with the cyanobiphenyls which have been widely studied and are known for their giant optical non-linearities.read more
Citations
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Journal ArticleDOI
Isotropic to smectic-A phase transition: A review
TL;DR: In this article, the authors present an attempt towards a unified picture of the direct transition from the isotropic to smectic-A phase, including structure and nature revealed by experiments, molecular models and Landau-de Gennes theory.
Journal ArticleDOI
New divergent dynamics in the isotropic to nematic phase transition of liquid crystals measured with 2D IR vibrational echo spectroscopy
TL;DR: The isotropic-nematic phase transition in liquid crystals is described in the context of the slowing of orientational relaxation associated with divergent growth of the orientational correlation length, and the correlation length of the density fluctuations is diverging with the same temperature dependence as the pseudonematic domain correlation length.
Journal ArticleDOI
Large Electro-Optic Kerr Effect in Ionic Liquid Crystals: Connecting Features of Liquid Crystals and Polyelectrolytes.
M. Christian Schlick,Nadia Kapernaum,Manuel M. Neidhardt,Tobias Wöhrle,Yannick Stöckl,Sabine Laschat,Frank Giesselmann +6 more
TL;DR: It is shown that maximum Kerr constants in the order of several 10-11 m V-2 make ionic liquid crystals attractive as new class of functional materials in low-speed Kerr effect applications.
Journal ArticleDOI
Critical Slowing of Density Fluctuations Approaching the Isotropic-Nematic Transition in Liquid Crystals: 2D IR Measurements and Mode Coupling Theory.
TL;DR: A remarkable change in coupling occurs at ∼5 K above TNI, precisely where the rate of spectral diffusion in 5CB was observed to deviate from that of a similar nonmesogenic liquid.
Journal ArticleDOI
Length scales and structural dynamics in nematogen pseudonematic domains measured with 2D IR vibrational echoes and optical Kerr effect experiments.
TL;DR: The results demonstrate that the presence of local orientational order at temperatures well above TNI does not affect the spectral diffusion (structural evolution) within pseudonematic domains when the correlation lengths are short, and density fluctuations are likely the source of spectral diffusion at temperatures at least 5 Kabove TNI.
References
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Nonlinear Dielectric Polarization in Optical Media
TL;DR: The physical mechanisms which can produce second-order dielectric polarization are discussed on the basis of a simple extension of the theory of dispersion in ionic crystals in this paper.
Journal ArticleDOI
Optical Compensators for Measurement of Elliptical Polarization
TL;DR: A detailed survey of the present-day knowledge of optical compensators is given in this article, with a reference made to the sensitivity and accuracy of the compensators and their applications.
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Study of pretransitional behavior of laser-field-induced molecular alignment in isotropic nematic substances
George K.L. Wong,Y. R. Shen +1 more
TL;DR: In this paper, the authors measured the optical Kerr effect and the intensity-dependent ellipse rotation in order to study the pretransitional behavior of field-induced molecular alignment in the isotropic nematic substances.
Journal ArticleDOI
Nonlinear Susceptibility Constants and Self-Focusing of Optical Beams in Liquids
Journal ArticleDOI
The Order-Disorder Phase Transition in Liquid Crystals as a Function of Molecular Structure. I. The Alkyl Cyanobiphenyls
Harry J. Coles,C. Strazielle +1 more
TL;DR: In this paper, the authors studied the pretransitional behavior of a series of mesomorphic compounds, the alkyl cyanobiphenyls (CNρρC n H 2n + 1) for n = 5-12, and showed that the presence of the smectic A phase changes markedly the pret-ransitional behaviour, and gives rise to two distinct pret-transitional regions.
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