scholarly journals High Performance Holographic Polymer Dispersed Liquid Crystal Systems Formed with the Siloxane-containing Derivatives and Their Applications on Electro-optics

10.5772/8669 ◽  
2010 ◽  
Author(s):  
Yeonghee Cho ◽  
Yusuke Kawakami
Keyword(s):  
Liquid Crystal ◽  
High Performance ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed

scholarly journals Accurate, Efficient and Rigorous Numerical Analysis of 3D H-PDLC Gratings

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3725
Author(s):  
Jorge Francés ◽  
Sergio Bleda ◽  
Daniel Puerto ◽  
Sergi Gallego ◽  
Andrés Márquez ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
High Performance ◽  
Fdtd Method ◽  
Polymer Dispersed Liquid Crystal ◽  
Optical Media ◽  
Polymer Dispersed ◽  
3D Numerical Modelling ◽  
Anchoring Strength ◽  
Split Field

This work presents recent results derived from the rigorous modelling of holographic polymer-dispersed liquid crystal (H-PDLC) gratings. More precisely, the diffractive properties of transmission gratings are the focus of this research. This work extends previous analysis performed by the authors but includes new features and approaches. More precisely, full 3D numerical modelling was carried out in all analyses. Each H-PDLC sample was generated randomly by a set of ellipsoid geometry-based LC droplets. The liquid crystal (LC) director inside each droplet was computed by the minimisation of the Frank elastic free energy as a function of the applied electric field. The analysis carried out considered the effects of Frank elastic constants K11, K22 and K33; the anchoring strength W0; and even the saddle-splay constant K24. The external electric field induced an orientation of the LC director, modifying the optical anisotropy of the optical media. This effect was analysed using the 3D split-field finite-difference time-domain (SF-FDTD) method. In order to reduce the computational costs due to a full 3D tensorial analysis, a highly optimised method for high-performance computing solutions (HPC) was developed. The influences of the anchoring and voltage on the diffraction efficiencies were investigated, showing the potential of this approach.

scholarly journals Polymer Dispersed Cholesteric Liquid Crystals With a Toroidal Director Configuration under an Electric Field

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 732
Author(s):  
Anna P. Gardymova ◽  
Mikhail N. Krakhalev ◽  
Victor Ya. Zyryanov ◽  
Alexandra A. Gruzdenko ◽  
Andrey A. Alekseev ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Electric Field ◽  
Point Defects ◽  
Structural Response ◽  
Optical Filters ◽  
Response Curves ◽  
Polymer Dispersed Liquid Crystal ◽  
Dichroic Dye ◽  
Polymer Dispersed

The electro-optical properties of polymer dispersed liquid crystal (PDLC) films are highly dependent on the features of the contained liquid crystal (LC) droplets. Cholesteric LC droplets with homeotropic boundaries can form several topologically different orientational structures, including ones with single and more point defects, layer-like, and axisymmetric twisted toroidal structures. These structures are very sensitive to an applied electric field. In this work, we have demonstrated experimentally and by computer simulations that twisted toroidal droplets reveal strong structural response to the electric field. In turn, this leads to vivid changes in the optical texture in crossed polarizers. The response of droplets of different sizes were found to be equivalent in terms of dimensionless parameters. In addition, the explanation of this phenomenon showed a comparison of theoretical and experimental structural response curves aids to determine the shape of the droplet. Finally, we demonstrated that the addition of a dichroic dye allows such films to be used as optical filters with adjustable color even without polarizers.

Kinetics of Droplet Formation in UV-Cured Polymer-Dispersed Liquid Crystal Films

1994 ◽  
Vol 33 (Part 1, No. 5A) ◽  
pp. 2641-2647 ◽  
Author(s):  
Vasilii G. Nazarenko ◽  
Seshu Sarala ◽  
Nelamangala V. Madhusudana
Keyword(s):  
Liquid Crystal ◽  
Droplet Formation ◽  
Liquid Crystal Films ◽  
Polymer Dispersed Liquid Crystal ◽  
Crystal Films ◽  
Polymer Dispersed ◽  
Kinetics Of

scholarly journals Holographic Polymer-Dispersed Liquid Crystals: Materials, Formation, and Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-52 ◽  
Author(s):  
Y. J. Liu ◽  
X. W. Sun
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Refractive Index Profile ◽  
Single Step ◽  
Fast Switching ◽  
Polymer Dispersed Liquid Crystal ◽  
Current State ◽  
Index Matching ◽  
Polymer Dispersed ◽  
Materials Used

By combining polymer-dispersed liquid crystal (PDLC) and holography, holographic PDLC (H-PDLC) has emerged as a new composite material for switchable or tunable optical devices. Generally, H-PDLC structures are created in a liquid crystal cell filled with polymer-dispersed liquid crystal materials by recording the interference pattern generated by two or more coherent laser beams which is a fast and single-step fabrication. With a relatively ideal phase separation between liquid crystals and polymers, periodic refractive index profile is formed in the cell and thus light can be diffracted. Under a suitable electric field, the light diffraction behavior disappears due to the index matching between liquid crystals and polymers. H-PDLCs show a fast switching time due to the small size of the liquid crystal droplets. So far, H-PDLCs have been applied in many promising applications in photonics, such as flat panel displays, switchable gratings, switchable lasers, switchable microlenses, and switchable photonic crystals. In this paper, we review the current state-of-the-art of H-PDLCs including the materials used to date, the grating formation dynamics and simulations, the optimization of electro-optical properties, the photonic applications, and the issues existed in H-PDLCs.

LIQUID-CRYSTAL COMPOSITES: Multicolor Polymer-Dispersed Liquid Crystal (Adv. Mater. 7/2011)

2011 ◽  
Vol 23 (7) ◽  
pp. 883-883
Author(s):  
Naomi Kumano ◽  
Takahiro Seki ◽  
Masahiko Ishii ◽  
Hiroshi Nakamura ◽  
Tomonari Umemura ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed
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