Role of ionic contribution in dielectric behaviour of a nematic liquid crystal with variable cell thickness

2020 ◽  
Vol 303 ◽  
pp. 112520 ◽  
Author(s):  
Akash Kumar ◽  
Depanshu Varshney ◽  
Jai Prakash
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Dielectric Behaviour ◽  
Ionic Contribution ◽  
Cell Thickness

Surface-Induced Flexoelectric Domains in Asymmetrically Strong-Weak Anchored MBBA Films

1982 ◽  
Vol 37 (4) ◽  
pp. 334-341
Author(s):  
H. P. Hinov
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Dielectric Anisotropy ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Surface Anchoring ◽  
Threshold Voltages ◽  
Domain Period ◽  
Cell Thickness

Abstract The longitudinal surface-induced flexoelectric domains, previously obtained in symmetrically weak-anchored nematic layers have been further investigated in asymmetrically strong-weak anchored MBBA layers. The threshold voltages indicating the onset of the flexoelectric instabilities are high for thin cells (d = 9 μm, Uth = 10 V) and small for thick cells (d = 150 μm, Uth =1.5 V). Pronounced minima in the curves p vs. d and Uth vs. d, where p is the domain period and d is the cell thickness, were obtained. The flexoelectric domains were replaced by electrohydrodynamic instabilities only in the case of strong azimuthal anchoring of the liquid crystal layer.The role of the sign and the value of the dielectric anisotropy, the homogeneity of the electric field as well as the asymmetry in the surface anchoring are discussed in detail.

The elastic and optical properties of a bent-core thiadiazole nematic liquid crystal: the role of the bend angle

2013 ◽  
Vol 1 (13) ◽  
pp. 2416 ◽  
Author(s):  
S. Kaur ◽  
L. Tian ◽  
H. Liu ◽  
C. Greco ◽  
A. Ferrarini ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Bend Angle

The Role of Inertia and Dissipation in the Dynamics of the Director for a Nematic Liquid Crystal Coupled with an Electric Field

2015 ◽  
Vol 18 (1) ◽  
pp. 147-166 ◽  
Author(s):  
Peder Aursand ◽  
Johanna Ridder
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Relative Strength ◽  
Inertial Forces ◽  
Director Field ◽  
Voltage Difference ◽  
Electrostatic Equilibrium ◽  
Variational Wave

AbstractWe consider the dynamics of the director in a nematic liquid crystal when under the influence of an applied electric field. Using an energy variational approach we derive a dynamic model for the director including both dissipative and inertial forces.A numerical scheme for the model is proposed by extending a scheme for a related variational wave equation. Numerical experiments are performed studying the realignment of the director field when applying a voltage difference over the liquid crystal cell. In particular, we study how the relative strength of dissipative versus inertial forces influence the time scales of the transition between the initial configuration and the electrostatic equilibrium state.

scholarly journals Waveguided nematic liquid crystal random lasers

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yunxi Huang ◽  
Xiaojuan Zhang ◽  
Benli Yu ◽  
Jiajun Ma ◽  
Kang Xie ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Laser Intensity ◽  
Transmission Loss ◽  
Normal Direction ◽  
Horizontal Polarization ◽  
Random Lasers ◽  
Waveguide Effect ◽  
Highly Sensitive

Abstract In waveguided nematic liquid crystal random lasers (NLCRLs), we realize polarized random laser (RL) emission and discover that the waveguide effect reduces the transmission loss of the RL whose polarization is parallel to the liquid crystal molecules (LCMs). Compared with the traditional liquid crystal random lasers, the waveguide NLCRLs can achieve the regulation of RLs strength, polarization, and wavelength in the same structure. The electric field can drive the rotation of LCMs to control the RL polarization and intensity. The drop of horizontal polarization laser and the increase of vertical polarization laser prove the role of the waveguide effect. In addition, the disorder of the waveguided NLCRLs is highly sensitive to temperature, which makes it easy to control the wavelength and intensity of the RL. As the temperature rises, the waveguide effect is weakened, resulting in a weakening of the restriction along liquid crystal (LC) cell normal direction. The reduced laser intensity verifies the role of the waveguide effect.

ON THE BEHAVIOR OF POLARIZED LIGHT IN TWIST-ORIENTED NEMATIC LIQUID CRYSTALS WITH ANISOTROPIC ABSORBENT DYE

2020 ◽  
Vol 54 (1 (251)) ◽  
pp. 56-60
Author(s):  
H.H. Hovakimyan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Azimuthal Angle ◽  
Polarized Light ◽  
Transmitted Light ◽  
Propagation Of Light ◽  
Linearly Polarized ◽  
Incoming Light

In this work we study the propagation of light in a twist-oriented pleochroic nematic liquid crystal with pleochroic dye. The dependence of the intensity of transmitted light on the azimuthal angle of the linearly polarized incoming light has been investigated experimentally. As a result, the role of absorption anisotropy has been identified.

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