scholarly journals Flow-assisted self-healing of the helical structure in a cholesteric liquid crystal

2021 ◽  
Vol 155 (5) ◽  
pp. 054903
Author(s):  
Jan-Christoph Eichler ◽  
Robert A. Skutnik ◽  
Marco G. Mazza ◽  
Martin Schoen
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Helical Structure ◽  
Self Healing

scholarly journals Thermo-Chromic Response of Polymer Stabilized Cholesteric Liquid Crystal for Thermal Imaging

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Rishi Kumar
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermal Imaging ◽  
Cholesteric Liquid Crystal ◽  
Helical Structure ◽  
Cholesteric Liquid Crystals ◽  
Polymer Stabilized

Cholesteric liquid crystal (Ch-LC) exhibits many remarkable optical properties due to formation of a macroscopic helical structure. A low amount of monomer (5wt.%) is dispersed into cholesteric liquid crystal and get polymerized under UV radiations to form polymer stabilized cholesteric texture (PSCT). The thermo-chromic response made this device suitable for the developing applications in thermal imaging. Temperature based measurements of PSCT exploits the key property of some polymer stabilized cholesteric liquid crystals (PSCLC) to reflect definite colors at specific temperatures. The selective color of PSCT texture shifts with raise in temperature from 30oC to 85oC, which can be utilized in thermal imaging applications.

scholarly journals High-Reflective Templated Cholesteric Liquid Crystal Filters

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6889
Author(s):  
Yao Gao ◽  
Yuxiang Luo ◽  
Jiangang Lu
Keyword(s):  
Liquid Crystal ◽  
Bragg Reflection ◽  
Cholesteric Liquid Crystal ◽  
Polarized Light ◽  
Single Layer ◽  
Helical Structure ◽  
Optical Filters ◽  
Blue Color ◽  
Phase Liquid ◽  
Multi Phase

Cholesteric liquid crystals (CLCs) have been widely applied in optical filters due to Bragg reflection caused by their helical structure. However, the reflectivity of CLC filters is relatively low, commonly less than 50%, as the filters can only reflect light polarized circularly either left- or right-handedly. Therefore, a high-reflective CLC filter with a single-layer template was proposed which may reflect both right- and left-handed polarized light. The CLC filters of the red, green, blue color were fabricated by the templating technology, which show good wavelength consistency. Additionally, a multi-phase liquid crystal filter with high reflectance was demonstrated by the single-layer templating technology. The templated CLC or multi-phase liquid crystal filters show great potential applications in the optical community, reflective display, and lasing.

scholarly journals Electrically tunable laser based on oblique heliconical cholesteric liquid crystal

2016 ◽  
Vol 113 (46) ◽  
pp. 12925-12928 ◽  
Author(s):  
Jie Xiang ◽  
Andrii Varanytsia ◽  
Fred Minkowski ◽  
Daniel A. Paterson ◽  
John M. D. Storey ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Cholesteric Liquid Crystal ◽  
Visible Spectrum ◽  
Tunable Laser ◽  
Helical Structure ◽  
Acute Angle ◽  
Helical Axis ◽  
Harmonic Structure ◽  
Tunable Range

A cholesteric liquid crystal (CLC) formed by chiral molecules represents a self-assembled one-dimensionally periodic helical structure with pitch p in the submicrometer and micrometer range. Because of the spatial periodicity of the dielectric permittivity, a CLC doped with a fluorescent dye and pumped optically is capable of mirrorless lasing. An attractive feature of a CLC laser is that the pitch p and thus the wavelength of lasing λ¯ can be tuned, for example, by chemical composition. However, the most desired mode to tune the laser, by an electric field, has so far been elusive. Here we present the realization of an electrically tunable laser with λ¯ spanning an extraordinarily broad range (>100 nm) of the visible spectrum. The effect is achieved by using an electric-field-induced oblique helicoidal (OH) state in which the molecules form an acute angle with the helicoidal axis rather than align perpendicularly to it as in a field-free CLC. The principal advantage of the electrically controlled CLCOH laser is that the electric field is applied parallel to the helical axis and thus changes the pitch but preserves the single-harmonic structure. The preserved single-harmonic structure ensures efficiency of lasing in the entire tunable range of emission. The broad tuning range of CLCOH lasers, coupled with their microscopic size and narrow line widths, may enable new applications in areas such as diagnostics, sensing, microscopy, displays, and holography.

Dispersion of proton spin-lattice relaxation in a cholesteric liquid crystal

1983 ◽  
Vol 44 (10) ◽  
pp. 1179-1184 ◽  
Author(s):  
M. Vilfan ◽  
R. Blinc ◽  
J. Dolinšek ◽  
M. Ipavec ◽  
G. Lahajnar ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Spin Lattice

Liquid Crystal Trimers Incorporating Saturated Isosteres of Benzene and Exhibiting Modulated Nematic Phases

2019 ◽  
Author(s):  
Adam Al-Janabi ◽  
Richard Mandle
Keyword(s):  
Liquid Crystal ◽  
Helical Structure ◽  
Molecular Shape ◽  
Saturated Hydrocarbons ◽  
Fluid System ◽  
Structural Requirement ◽  
Disubstituted Benzene ◽  
Bona Fide ◽  
Nematic Phases ◽  
Bend Angles

<p>The nematic twist-bend (N<sub>TB</sub>) liquid crystal phase possesses a local helical structure with a pitch length of a few nanometres and is the first example of spontaneous symmetry breaking in a fluid system. All known examples of the N­<sub>TB­</sub> phase occur in materials whose constituent mesogenic units are aromatic hydrocarbons. It is not clear if this is due to synthetic convenience or a <i>bona fide</i> structural requirement for a material to exhibit this phase of matter. In this work we demonstrate that materials consisting largely of saturated hydrocarbons could also give rise to this mesophase. Furthermore, replacement of 1,4-disubstituted benzene with <i>trans</i> 1,4-cyclohexane or even 1,4-cubane does not especially alter the transition temperatures of the resulting material nor does it appear to impact upon the heliconical tilt angle, suggesting the local structure of the phase is unperturbed. Calculating the probability distribution of bend angles reveals that the choice of isosteric group has little impact on the overall molecular shape, demonstrating the shape-driven nature of the N<sub>TB</sub> phase. </p>

scholarly journals The temperature dependence of the helical pitch in a cholesteric liquid crystal

2021 ◽  
pp. e1881638
Author(s):  
Robert A. Skutnik ◽  
Jan-Christoph Eichler ◽  
Marco G. Mazza ◽  
Martin Schoen
Keyword(s):  
Liquid Crystal ◽  
Temperature Dependence ◽  
Cholesteric Liquid Crystal ◽  
Helical Pitch
Sign in / Sign up

Export Citation Format

Share Document