Hysteresis and memory factor of the Kerr effect in blue phases

Nordendorf, Gaby; Lorenz, Alexander; Hoischen, Andreas; Schmidtke, Jürgen; Kitzerow, Heinz‐S.; Wilkes, David; Wittek, Michael

doi:10.1063/1.4828477

Cited by 17 publications

(23 citation statements)

References 32 publications

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“…3,6,8 Moreover, the coupling with the electric field is also very similar to other aqueous systems of rod-like or plate-like particles 19,22,41 showing therefore that ethylene glycol as electrolyte combined with well-defined anisometric nanoparticles represent a promising way for their use in electro-optical devices. The response of the system was probed both in an In-Plane Switching cells in which the electrodes are in direct contact with the sample, and also in the geometry of externally applied field.…”

Section: Discussionmentioning

confidence: 69%

“…This electro-optical effect has been observed on a wide spectrum of materials, ranging from thermotropic molecular compounds (exhibiting a temperature dependent phase behavior) used in LCDs [1][2][3][4][5][6][7][8][9] to lyotropic dispersions of anisometric colloidal nanoparticles (whose phase behavior is concentration dependent), 10 such as filamentous viruses, 11,12 pigment particles, 13,14 silica rods 15,16 or graphene oxide sheets. 1,2 When applied to a liquid crystalline sample, the external electric field induces usually a reorientation of the mesogens along or perpendicular to the field.…”

Section: Introductionmentioning

confidence: 99%

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Electric field induced birefringence in non-aqueous dispersions of mineral nanorods

et al. 2015

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Lanthanum phosphate (LaPO4) nanorods dispersed in the non-aqueous solvent of ethylene glycol form a system exhibiting large intrinsic birefringence, high colloidal stability and the ability to self-organize into liquid crystalline phases. In order to probe the electro-optical response of these rod dispersions we study here the electric-field-induced birefringence, also called Kerr effect, for a concentrated isotropic liquid state with an in-plane a.c. sinusoidal electric field, in conditions of directly applied (electrodes in contact with the sample) or externally applied (electrodes outside the sample cell) fields. Performing an analysis of the electric polarizability of our rod-like particles in the framework of Maxwell-Wagner-O'Konski theory, we account quantitatively for the coupling between the induced steady-state birefringence and the electric field as a function of the voltage frequency for both sample geometries. The switching time of this non-aqueous transparent system has been measured, and combined with its high Kerr coefficients and its features of optically isotropic "off-state" and athermal phase behavior, this represents a promising proof-of-concept for the integration of anisotropic nanoparticle suspensions into a new generation of electro-optical devices.

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Section: Discussionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Electric field induced birefringence in non-aqueous dispersions of mineral nanorods

et al. 2015

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“…(a) Examples of the basic components of polymer‐stabilized blue phase systems. Top: Nematic liquid crystal (NLC) component with high dielectric anisotropy and chiral dopants with high helical twisting power (ZLI‐4572, Merck, ISO‐(6OBA) 2, R‐5011, Merck). Below: Photoreactive monomers used for polymer‐stabilization {(2‐ethyl‐hexyl)‐acrylate (EHA), mesogenic reactive monomer RM‐257 (Merck), mesogenic monofunctional reactive monomer 6CBA and non‐mesogenic tri‐functional monomer trimethylolpropane triacrylate (TMPTA)}.…”

Section: Blue Phase Stabilizationmentioning

confidence: 99%

Polymer‐stabilized blue phases: promising mesophases for a new generation of liquid crystal displays

Nordendorf

Hoischen

Schmidtke

et al. 2014

Polymers for Advanced Techs

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Blue phases—special chiral liquid crystalline mesophases—are promising candidates for electro‐optic devices with improved performance and simplified fabrication. A necessary precondition for possible applications is a significantly enhanced temperature range of their existence, which can be achieved by a cross‐linked polymer network formed by in situ polymerization. Unlike many other mesophases, blue phases are optically isotropic if no voltage is applied. Regarding the transmission of a blue phase cell placed between crossed polarizers, the optical isotropy enables—at least in principle—a perfect dark state, independent of the viewing angle, without the necessity of any alignment layer. The application of an in‐plane electric field induces a strong birefringence (Kerr effect). The effective Kerr constants are much larger than those of isotropic liquids, and the switching times between the dark and the induced bright state are in the submillisecond range. Some basic properties of blue phases, state‐of‐the‐art performance, and remaining challenges of the development of polymer‐stabilized blue phases are reviewed in this article. Copyright © 2014 John Wiley & Sons, Ltd.

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“…Further experiments are needed to determine the response of the material at different wavelengths and a full investigation into the optimization of the composition of the liquid crystal material used [23,24]. Optimal composition of the polymer mixture for this blue phase and its overall concentration needs to be investigated.…”

Section: Resultsmentioning

confidence: 99%

“…This investigation shows that the BP is promising material for future LCoS SLM devices in many applications, offering high-speed, polarization insensitive [6,7] phase modulation. With careful manipulation of the BP material composition [23,24] to increase the response, operating temperature, and device thickness, it will be possible to offer full 2π phase modulation in the future, creating an LCoS SLM device with highly desirable properties.…”

Section: Discussionmentioning

confidence: 98%

Polarization-independent phase modulation using a blue-phase liquid crystal over silicon device

et al. 2014

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Liquid crystal over silicon (LCoS) spatial light modulator technology has become dominant in industries such as pico-projection, which require high-quality reflective microdisplays for intensity modulation of light. They are, however, restricted from being used in wider optical applications, such as computer-generated holography, adaptive optics, and optical correlation, due to their phase modulation ability. The main drawback of these devices is that their modulation is based on simple planar or twisted nematic liquid crystals, which are inherently slow mechanisms due to their viscoelastic properties. Their use is also limited due to fact that the phase modulation is dependent on the state of polarization of the illumination. In this paper, we demonstrate that a polymer-stabilized blue-phase liquid crystal can offer both phase modulation and high speed switching in a silicon backplane device which is independent of the input polarization state. The LCoS device shows continuous phase modulation of light with a submillisecond switching time and insensitivity to the input light polarization direction. This type of phase modulation opens up a whole new class of applications for LCoS technology.

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Hysteresis and memory factor of the Kerr effect in blue phases

Cited by 17 publications

References 32 publications

Electric field induced birefringence in non-aqueous dispersions of mineral nanorods

Electric field induced birefringence in non-aqueous dispersions of mineral nanorods

Polymer‐stabilized blue phases: promising mesophases for a new generation of liquid crystal displays

Polarization-independent phase modulation using a blue-phase liquid crystal over silicon device

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