scholarly journals Liquid Crystals: Electrically Switchable Diffraction Grating Using a Hybrid Liquid Crystal and Carbon Nanotube-Based Nanophotonic Device (Advanced Optical Materials 5/2013)

2013 ◽  
Vol 1 (5) ◽  
pp. 367-367
Author(s):  
Kanghee Won ◽  
Ananta Palani ◽  
Haider Butt ◽  
Philip J. W. Hands ◽  
Ranjith Rajeskharan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Liquid Crystals ◽  
Diffraction Grating ◽  
Optical Materials ◽  
Nanophotonic Device

scholarly journals Electrically Switchable Diffraction Grating Using a Hybrid Liquid Crystal and Carbon Nanotube-Based Nanophotonic Device

2013 ◽  
Vol 1 (5) ◽  
pp. 368-373 ◽  
Author(s):  
Kanghee Won ◽  
Ananta Palani ◽  
Haider Butt ◽  
Philip J. W. Hands ◽  
Ranjith Rajeskharan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Diffraction Grating ◽  
Nanophotonic Device

scholarly journals Chiral Liquid Crystals: Tilted Chiral Liquid Crystal Gratings for Efficient Large‐Angle Diffraction (Advanced Optical Materials 22/2019)

2019 ◽  
Vol 7 (22) ◽  
pp. 1970086
Author(s):  
Inge Nys ◽  
Migle Stebryte ◽  
Yera Ye. Ussembayev ◽  
Jeroen Beeckman ◽  
Kristiaan Neyts
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Materials ◽  
Large Angle ◽  
Chiral Liquid Crystal ◽  
Chiral Liquid Crystals

Electric-Field Effects in Dilute Suspensions of Carbon Nanotubes Dispersed in Nematic Liquid Crystals

2010 ◽  
Vol 428-429 ◽  
pp. 173-181 ◽  
Author(s):  
Muklesur Rahman ◽  
Wei Lee
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Colloidal Particles ◽  
Liquid Crystal Display ◽  
New Physics ◽  
Colloidal System ◽  
Colloidal Systems

Colloids composed of liquid-crystal hydrosols exhibit a rich set of interesting phenomena. The coupling between liquid-crystalline media and colloidal particles plays an essential role leading to an abundant source of new physics. In the last few years, peculiar behaviors of carbon-nanotube-doped calamitic liquid crystals have attracted considerable attention. This paper provides a brief introduction to this alluring subject for its on-going research development in this laboratory. First presented are our current understandings of the nematic colloidal system comprising carbon nanotubes and of their possible orientation and dynamics under the application of an external field. Various electro-optical and electrical properties of a liquid-crystal display rectified by the nanoscale carbonaceous guest are then addressed to a larger extent. Dielectric relaxation obtained from a nematic impregnated with carbon nanotubes is also discussed. With historical significance for the dawn of the liquid-crystal–carbon-nanotube research, several important findings of enhanced nonlinear optical properties in typical nematic mesomaterials consisting of suspended nanotubes are delineated. With the new colloidal systems of elongated nanoscale solids dispersed in anisotropic fluids in the mesophase, many new intriguing phenomena are awaiting theoretical and experimental explorations. Collaborations are called to draw attention of interested theoretical physicists, in particular.

scholarly journals Nematic Liquid Crystal Composite Materials for DC and RF Switching

Technologies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 32 ◽  
Author(s):  
Mohiuddin Munna ◽  
Farhana Anwar ◽  
Ronald Coutu
Keyword(s):  
Electrical Conductivity ◽  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Composite Materials ◽  
Liquid Crystals ◽  
Local Heating ◽  
Device Fabrication ◽  
Pure Liquid ◽  
Dual Frequency ◽  
Concentration Effects

Liquid Crystals (LCs) are widely used in display devices, electro-optic modulators, and optical switches. A field-induced electrical conductivity modulation in pure liquid crystals is very low which makes it less preferable for direct current (DC) and radio-frequency (RF) switching applications. According to the literature, a conductivity enhancement is possible by nanoparticle doping. Considering this aspect, we reviewed published works focused on an electric field-induced conductivity modulation in carbon nanotube-doped liquid crystal composites (LC-CNT composites). A two to four order of magnitude switching in electrical conductivity is observed by several groups. Both in-plane and out-of-plane device configurations are used. In plane configurations are preferable for micro-device fabrication. In this review article, we discussed published works reporting the elastic and molecular interaction of a carbon nanotube (CNT) with LC molecules, temperature and CNT concentration effects on electrical conductivity, local heating, and phase transition behavior during switching. Reversibility and switching speed are the two most important performance parameters of a switching device. It was found that dual frequency nematic liquid crystals (DFNLC) show a faster switching with a good reversibility, but the switching ratio is only two order of magnitudes. A better way to ensure reversibility with a large switching magnitude is to use two pairs of in-plane electrodes in a cross configuration. For completeness and comparison purposes, we briefly reviewed other nanoparticle- (i.e., Au and Ag) doped LC composite’s conductivity behavior as well. Finally, based on the reported works reviewed in this article on field induced conductivity modulation, we proposed a novel idea of RF switching by LC composite materials. To support the idea, we simulated an LC composite-based RF device considering a simple analytical model. Our RF analysis suggests that a device made with an LC-CNT composite could show an acceptable performance. Several technological challenges needed to be addressed for a physical realization and are also discussed briefly.

Optical phase modulation using a hybrid carbon nanotube-liquid-crystal nanophotonic device

2009 ◽  
Vol 34 (8) ◽  
pp. 1237 ◽  
Author(s):  
Ranjith Rajasekharan-Unnithan ◽  
Haider Butt ◽  
Timothy D. Wilkinson
Keyword(s):  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Phase Modulation ◽  
Optical Phase ◽  
Optical Phase Modulation ◽  
Nanophotonic Device ◽  
Hybrid Carbon

New structure induced by elastic anisotropy in cylindrical nematic liquid crystal

2017 ◽  
Vol 13 (2) ◽  
pp. 4705-4717
Author(s):  
Zhang Qian ◽  
Zhou Xuan ◽  
Zhang Zhidong
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals ◽  
Gennes Theory

Basing on Landau–de Gennes theory, this study investigated the chiral configurations of nematic liquid crystals confined to cylindrical capillaries with homeotropic anchoring on the cylinder walls. When the elastic anisotropy (L2/L1) is large enough, a new structure results from the convergence of two opposite escape directions of the heterochiral twist and escape radial (TER) configurations. The new defect presents when L2/L1≥7 and disappears when L2/L1<7. The new structure possesses a heterochiral hyperbolic defect at the center and two homochiral radial defects on both sides. The two radial defects show different chiralities.

scholarly journals Liquid Crystal Devices for Beam Steering Applications

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 247
Author(s):  
Rowan Morris ◽  
Cliff Jones ◽  
Mamatha Nagaraj
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Adaptive Optics ◽  
Beam Steering ◽  
Optical Components ◽  
Advantages And Disadvantages ◽  
Liquid Crystal Devices

Liquid crystals are valuable materials for applications in beam steering devices. In this paper, an overview of the use of liquid crystals in the field of adaptive optics specifically for beam steering and lensing devices is presented. The paper introduces the properties of liquid crystals that have made them useful in this field followed by a more detailed discussion of specific liquid crystal devices that act as switchable optical components of refractive and diffractive types. The relative advantages and disadvantages of the different devices and techniques are summarised.

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