General properties of lasing effect in chiral liquid crystals

2006 ◽  
Vol 14 (4) ◽  
Author(s):  
S. Palto ◽  
N. Shtykov ◽  
B. Umansky ◽  
M. Barnik ◽  
L. Blinov
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Numerical Simulations ◽  
Light Emission ◽  
Experimental Studies ◽  
General Properties ◽  
Chiral Liquid Crystals ◽  
Lasing Condition

AbstractNumerical simulations and experimental studies of the lasing effect in chiral liquid crystals are presented. It is shown that ring-like light emission, which is often observed experimentally, is a true lasing effect. Lasing condition and different modes in thin liquid crystal layers are discussed.

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

scholarly journals Holographic Formation of Non-uniform Diffraction Structures by Arbitrary Polarized Recording Beams in Liquid Crystal-photopolymer Compositions

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 861 ◽  
Author(s):  
Artem Semkin ◽  
Sergey Sharangovich
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Numerical Simulations ◽  
Polarization State ◽  
Dielectric Tensor ◽  
Arbitrary Polarization ◽  
Recording Process ◽  
Polymer Dispersed ◽  
The Media ◽  
Light Beams

In this work, the theoretical model of non-uniform diffraction structures’ holographic formation in liquid crystal-photopolymer (LC-PPM) composite materials with a dye-sensitizer is developed. The model takes into account the arbitrary character of amplitude and phase spatial distributions of recording light field, its arbitrary polarization state and also a non-linearity of the recording process. Two the most common types of liquid crystal-photopolymer composite are investigated: Holographic polymer-dispersed liquid crystals (H-PDLC) and polymer-stabilized liquid crystals (PSLC). Numerical simulations for the most common cases of holographic formation schemes are made. It is shown that due to the photo-induced Freedericksz transition, in the case of arbitrary polarization states of recording light beams, the non-uniform polarization diffraction grating (PDG) is formed in LC-PPM. Numerical simulations’ results show that PDG’s contribution to the change of the dielectric tensor of the media is comparable with the contribution of the photopolymerization-diffusion process.

Effect of the liquid crystal solute on the rotator phase transitions of n-alkanes

RSC Advances ◽  
2015 ◽  
Vol 5 (16) ◽  
pp. 12168-12177 ◽  
Author(s):  
Prabir K. Mukherjee
Keyword(s):  
Phase Transitions ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Binary Mixtures ◽  
Experimental Studies ◽  
Rotator Phase

Recent experimental studies have shown that the liquid crystal substance plays an important role in determining the structures and the phase transitions of the different rotator phases in binary mixtures of n-alkane and liquid crystals.

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.

Fault Verification Simulation for Light-Emission Microscopy and Liquid-Crystal Analysis

1996 ◽  
Author(s):  
N. Kuji ◽  
T. Takeda ◽  
S. Nakamura ◽  
Y. Komine
Keyword(s):  
Liquid Crystal ◽  
Light Emission ◽  
Logic Model ◽  
Spice Simulation ◽  
Logic Models ◽  
Model Derivation ◽  
Emission Microscopy ◽  
Derivation Method ◽  
Fault Verification

Abstract A new logic-model derivation method for leak faults observed by light-emission microscopy (LEM) or in liquid-crystal analysis (LCA) has been developed to verify those faults by comparing them with failures observed on an LSI tester. Since CMOS devices display various kinds of faulty behavior depending on leak resistance, it is essential to include the effects of this resistance in logic models. Considering that the resistance of leaks observed in LEM and LCA ranges from 10 to 10,000 ohm, the new logic models have been derived so that the leak fault could be easily incorporated into logic simulators without SPICE simulation. The feasibility of the proposed method has been demonstrated by using it to diagnose LEM and LCA faults causing logic failure in a 20k-gate logic LSI circuit.

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.

A 2*2 fiber optic switch using chiral liquid crystals

1990 ◽  
Vol 2 (2) ◽  
pp. 147-149 ◽  
Author(s):  
N.K. Shankar ◽  
J.A. Morris ◽  
C.P. Yakymyshyn ◽  
C.R. Pollock
Keyword(s):  
Liquid Crystals ◽  
Fiber Optic ◽  
Chiral Liquid Crystals

scholarly journals Optical Response Associated with the Orientation and Structure of Liquid Crystals with Respect to Phosphatidylcholine Concentration

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 678
Author(s):  
Yuqi Han ◽  
Yan Jiang ◽  
Wei Guo ◽  
Bing Li ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Reflectance Spectrum ◽  
Optical Response ◽  
The Self ◽  
Cholesteric Liquid Crystals ◽  
Anchoring Effect ◽  
Self Assembling ◽  
Sensitization Effect ◽  
Structure Of Liquid

Based on the anchoring effect due to the self-assembling behavior of the phospholipid molecules at the interface between the liquid crystal and water phases on the orientation of liquid crystals, the optical response associated with the orientation and structure of liquid crystals with respect to the concentration of 1,2-didodecanoyl-sn-glycero-3-phosphocholine solution has been investigated. The optical response owing to changes in the orientation and structure of the mixed cholesteric liquid crystals with respect to the change in the concentration of phosphatidylcholine has been obtained. Moreover, the feasibility of using as-prepared mixed cholesteric liquid crystals to measure the phosphatidylcholine concentration has been verified. A methodology to measure the reflectance spectrum by using mixed cholesteric liquid crystals to sensitize the phosphatidylcholine concentration has been further realized. The sensitization effect of the mixed cholesteric liquid crystals on the measurement of phosphatidylcholine concentration was also verified.

scholarly journals Optofluidic Platform Based on Liquid Crystals in X-Cut Lithium Niobate: Thresholdless All-Optical Response

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 908
Author(s):  
Fabrizio Ciciulla ◽  
Annamaria Zaltron ◽  
Riccardo Zamboni ◽  
Cinzia Sada ◽  
Francesco Simoni ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Light Intensity ◽  
Lithium Niobate ◽  
Photovoltaic Effect ◽  
Optical Control ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Threshold Behaviour ◽  
All Optical

In this study, we present a new configuration of the recently reported optofluidic platform exploiting liquid crystals reorientation in lithium niobate channels. In order to avoid the threshold behaviour observed in the optical control of the device, we propose microchannels realized in a x-cut crystal closed by a z-cut crystal on the top. In this way, the light-induced photovoltaic field is not uniform inside the liquid crystal layer and therefore the conditions for a thresholdless reorientation are realized. We performed simulations of the photovoltaic effect based on the well assessed model for Lithium Niobate, showing that not uniform orientation and value of the field should be expected inside the microchannel. In agreement with the re-orientational properties of nematic liquid crystals, experimental data confirm the expected thresholdless behaviour. The observed liquid crystal response exhibits two different regimes and the response time shows an unusual dependence on light intensity, both features indicating the presence of additional photo-induced fields appearing above a light intensity of 107 W/m2.

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