scholarly journals Annihilation dynamics of topological defects induced by microparticles in nematic liquid crystals

Soft Matter ◽  
2019 ◽  
Vol 15 (43) ◽  
pp. 8749-8757 ◽  
Author(s):  
Yuan Shen ◽  
Ingo Dierking
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Topological Defects ◽  
Field Conditions ◽  
Viscous Drag ◽  
Complex Interplay ◽  
Drag Forces ◽  
Micro Particles

The annihilation dynamics of liquid crystal topological defects with micro-particles is governed by a complex interplay between elastic attraction, backflow, viscous drag forces, confinement and applied electric field conditions.

Nano-Sized Fine Droplets of Liquid Crystals for Optical Application

1996 ◽  
Vol 457 ◽  
Author(s):  
Shiro Matsumoto ◽  
Marthe Houlbert ◽  
Takayoshi Hayashi ◽  
Ken-ichi Kubodera
Keyword(s):  
Liquid Crystal ◽  
Phase Separation ◽  
Liquid Crystals ◽  
Electric Field ◽  
Applied Voltage ◽  
Applied Electric Field ◽  
Uv Curing ◽  
Infrared Region ◽  
High Transparency ◽  
Power Change

ABSTRACTNano-sized fine droplets of liquid crystal (LC) were obtained by phase separation of nematic LC in UV curing polymer. The polymer composite had a high transparency in the infrared region. The fine droplets responded to an electric field causing a change in birefringence. Output power change was brought about by the generated retardation between two polarizations, parallel and perpendicular to the applied electric field. This differs from the composite containing much larger droplets, where output depends on the degree of scattering. The birefringence changed by 0.001 at the applied voltage of 7.5 V/μm.

The breathers in nematic liquid crystals under applied electric field

2019 ◽  
Vol 33 (26) ◽  
pp. 1950319
Author(s):  
Yan Li ◽  
Xiaobo Lu ◽  
Chunfeng Hou
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Dynamic Equation ◽  
Applied Electric Field ◽  
Deflection Angle ◽  
Breather Solution ◽  
The Relationship ◽  
Sg Equation

In this paper, we study the twist of the nematic liquid crystal molecules under the applied electric field. The dynamic equation of the twisted molecules is derived. It is proved to be a kind of sine-Gordon (SG) equation. We obtain the breather solution of the equation and confirm that the deflection angles of the twisted molecules can distribute in the form of breathers. We give the relationship between the molecular deflection angle and the breather frequency, and discuss the effect of electric field on breather shape and breather frequency.

Microsecond Time-Resolved Infrared Study of the Electric-Field-Induced Reorientation of Nematic Liquid Crystals. Part II: Dependence of the Motion of Liquid Crystals on the Applied Electric Field

1993 ◽  
Vol 47 (12) ◽  
pp. 2108-2113 ◽  
Author(s):  
Taeko I. Urano ◽  
Hiro-O Hamaguchi
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Slow Component ◽  
Fast Component ◽  
Rigid Core ◽  
Time Resolved ◽  
Flexible Part ◽  
Reorientation Motion

The electric-field dependence of the reorientation motion of a nematic liquid crystal, 5CB (4- n-pentyl-4'-cyanobiphenyl), has been studied by microsecond time-resolved infrared spectroscopy. A rectangular pulsed electric field with a short pulse duration (2 ms) and a low repetition rate (5 Hz) was used to examine the liquid crystal (LC) response in a silicon cell. The motion of the rigid core part (the cyanobiphenyl group) of 5CB was monitored by the CN stretch band and that of the flexible part (the pentyl group) by the pentyl CH stretch band. The response of the LC to the pulsed electric field consists of two components, the slow component and the fast component. The slow component is common to the rigid core and the flexible parts of SCB. The voltage dependence of the slow component exhibits a clear threshold, indicating that this component corresponds to a cooperative motion of the 5CB molecules. The fast component is specific to the flexible part and shows exponential rise and decay behavior patterns. This observation suggests that the fast component corresponds to some noncooperative motions which are characteristic of the pentyl group. It is most likely that the internal rotation around the C(biphenyl)-C(pentyl) bond is responsible for the fast component. It is suggested that the LC molecules near the cell interface play a key role in the primary stage of the reorientation motion under an applied electric field.

scholarly journals Manipulation of colloids by optical and electrical control of disclination lines in liquid crystals

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
D. Kasyanyuk ◽  
P. Pagliusi ◽  
A. Mazzulla ◽  
S. Tomylko ◽  
V. Reshetnyak ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Boundary Conditions ◽  
Applied Voltage ◽  
Topological Defects ◽  
Different Boundary Conditions ◽  
Electrical Control ◽  
Micro Particles ◽  
Continuous Displacement ◽  
Anisotropic Fluids

AbstractWe report two viable strategies to assemble and manipulate arrays of nano- and micro-particles by means of topological defects (TDs) in anisotropic fluids. Exploiting different boundary conditions, single TD, 1D arrays of TDs are tailored in liquid crystal twist cells. In a first approach, light-guided control of particles captured in disclination lines is demonstrated involving the use of a photosensitive chiral dopant within a nematic host. In the second one, an applied voltage enables a continuous displacement and deformation of the particles arrays. The reported results open up new possibilities for managing nano- and micro-metric objects over large distances.

LIQUID CRYSTLASLIGHT SCATTERING BY FLUCTUATIONS INDUCED BY AN APPLIED ELECTRIC FIELD IN A NEMATIC LIQUID CRYSTAL (APAPA)

1972 ◽  
Vol 33 (C1) ◽  
pp. C1-63-C1-67 ◽  
Author(s):  
M. BERTOLOTTI ◽  
B. DAINO ◽  
P. Di PORTO ◽  
F. SCUDIERI ◽  
D. SETTE
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Applied Electric Field

Investigation on dynamic holographic display in liquid crystal film doped with carbon dots

2020 ◽  
Vol 10 (6) ◽  
pp. 780-787
Author(s):  
Hongyue Gao ◽  
Suna Li ◽  
Jicheng Liu ◽  
Wen Zhou ◽  
Fan Xu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Real Time ◽  
Diffraction Efficiency ◽  
Carbon Dots ◽  
Applied Electric Field ◽  
Light Polarization ◽  
Forming Process ◽  
Time Dynamic ◽  
Holographic Display

In this paper, we studied the holographic properties of liquid crystal (LC) thin film doped with carbon dots (CDs) which can be used as real-time holographic display screen. The maximum value of diffraction efficiency can reach up to 30% by using a low applied electric field 0.2 V/μm. Holograms in the LC film can be dynamically formed and self-erased. The hologram build-up time and the hologram self-erasure time in the material is fast enough to realize video refresh rate. In addition, the forming process of hologram was studied. The holographic diffraction efficiency was measured depending on the intensity of recording light, applied electric field, the intensity of readout light, and readout light polarization direction. Triple enhancement of the diffraction efficiency value by the modulation of voltage under the condition of low recording energy is presented. Therefore, we develop an easy way to obtain real-time dynamic holographic red, green and blue displays with high diffraction efficiency, which allow the LC film doped with CDs to be used as a holographic 3D display screen.

scholarly journals Evaluation of 4-alkoxy-4′-nitrobiphenyl liquid crystals for use in next generation scattering LCDs

RSC Advances ◽  
2017 ◽  
Vol 7 (64) ◽  
pp. 40480-40485 ◽  
Author(s):  
Richard J. Mandle ◽  
Stephen J. Cowling ◽  
John W. Goodby
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Field Studies ◽  
Next Generation ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

A combination of microscopy, X-ray scattering, calorimetry and applied electric field studies demonstrates the 4-alkoxy-4′-nitrobiphenyls are potentially of use for next generation, backlight free scattering mode LCD devices.

scholarly journals Electrically tuned whispering gallery modes microresonator based on microstructured optical fibers infiltrated with dual-frequency liquid crystals

Nanophotonics ◽  
2018 ◽  
Vol 7 (7) ◽  
pp. 1333-1340 ◽  
Author(s):  
Chengkun Yang ◽  
Hao Zhang ◽  
Bo Liu ◽  
Haifeng Liu ◽  
Chao Wang ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Optical Fibers ◽  
Applied Electric Field ◽  
Optical Switching ◽  
Resonance Wavelength ◽  
Crossover Frequency ◽  
Dual Frequency ◽  
Whispering Gallery ◽  
Operation Frequency

AbstractAn electrically tunable whispering gallery mode (WGM) microresonator based on an HF-etched microstructured optical fiber (MOF) infiltrated with dual-frequency liquid crystals (DFLCs) is proposed and experimentally demonstrated for the investigation of the crossover frequency and Freedericksz transition of DFLCs. Experimental results indicate that for applied electric field with operation frequency below the crossover frequency, WGM resonance wavelength decreases with the increment of applied electric field strength. On the contrary, for applied electric field with operation frequency beyond the crossover frequency, WGM resonance dips show red shift as the applied electric field intensity increases. The proposed electrically tunable microcavity integrated with DFLCs is anticipated to find potential applications in optical filtering, all-optical switching, and electrically manipulated bi-directional micro-optics devices.

Electrically switchable reflection gratings in polymer dispersed liquid crystals

1999 ◽  
Vol 559 ◽  
Author(s):  
L. V. Natarajan ◽  
R. L. Sutherland ◽  
V. P. Tondiglia ◽  
S. Siwecki ◽  
R. Pogue ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Low Voltage ◽  
Blue Shift ◽  
Maximum Efficiency ◽  
Acrylate Monomer ◽  
Polymer Dispersed ◽  
Reflection Gratings ◽  
Grating Formation

ABSTRACTElectrically switchable volume reflection holograms were written by inhomogeneous illumination of a prepolymer syrup containing a nematic liquid crystal and a multifunctional acrylate monomer. Switchable holograms are diffractive optics structures and the diffraction efficiency can be controlled by the application of an electric field. Reflection gratings with grating spacing varying between 0.16-0.27 µm were made during the phase separation of liquid crystals from the fast curing prepolymer syrup. The reflection efficiency of the holograms were electrically modulated with the applied field of ∼10-15V/µm. Real time study of the grating formation revealed that the maximum efficiency is reached in ∼15 seconds. The shrinkage of the host polymer during grating formation resulted in the blue shift of the reflection notch. The response time of the grating in an electric field is ∼50 µs. Low voltage scanning electron microscope studies showed the presence of discrete nematic droplet domains of sizes 30-60 nm in liquid crystal rich region.

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