scholarly journals Liquid crystals for space instrumentation: optical properties of liquid crystal mixtures for polarimeters

2019 ◽  
Vol 9 (6) ◽  
pp. 2681 ◽  
Author(s):  
Pilar García Parejo ◽  
Alberto Álvarez-Herrero
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Space Instrumentation

Textural Spectral Characteristics of the Cholesteric Liquid Crystal

2010 ◽  
Vol 428-429 ◽  
pp. 241-246
Author(s):  
Jia Ling Wang ◽  
Xin Du ◽  
Jia Lv ◽  
Tian Chi Yu ◽  
Zhi Xin Fan
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cholesteric Liquid Crystal ◽  
Spectral Characteristics ◽  
Optoelectronic Devices ◽  
Liquid Crystal Displays ◽  
Transmission Property ◽  
Large Crystal ◽  
Important Significance

For the cholesteric liquid crystal (hereinafter short for Ch-LC) possesses special optical properties, it has specific applications in the area of liquid crystal displays and optoelectronic devices. Specimens of Ch-LCs in planar and focal conic texture stably are prepared. The photographs of textures are shot by polarizing microscope and transmittance spectrums of different textures are measured by spectrophotometer. It is found that the specimen in focal conic texture with large crystal domains has the well transmission property. The experiment has an important significance for applications of liquid crystals.

Research on Non-Electric Readout Infrared Thermal Imaging Detection Technology Based on the Liquid Crystal

2011 ◽  
Vol 181-182 ◽  
pp. 293-296
Author(s):  
Chang Long Cai ◽  
Ya Zhang ◽  
Xiao Ling Niu ◽  
Wei Guo Liu
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermal Imaging ◽  
Optical Rotation ◽  
Cholesteric Liquid Crystals ◽  
Isotropic Liquid ◽  
Infrared Thermal Imaging ◽  
Detection Technology ◽  
Imaging Detection

Liquid crystal, as a condensed matter, is a phase state between crystal and isotropic liquid. On the one hand, it has mobility and continuity as a liquid, and on the other hand, it has arranging ordering as a crystal, then it has many unique properties. Because the factors, such as heat, electric field, magnetic field, pressure, and so on, will easily influence the arranging of liquid crystal molecular, so once it is excited externally, its optical properties will be changed. At present, most research on the theory and application of liquid crystal mainly focus on the display. Thermo-optic effect is defined as the phenomenon that the optical properties of liquid crystal change with the changing of temperature. At the phase transition point, the thermo-optic effect of liquid crystal is very obvious. In this paper, non-electric readout infrared thermal imaging detection technology based on the optical rotation property of the cholesteric liquid crystals is mainly researched. Through the research, the cholesteric liquid crystals’ light curves, gray value curves and CCD image were obtained under different temperatures; it proved that using the optical rotation property of cholesteric liquid crystals to achieve the infrared imaging of hot objects is possible.

scholarly journals Frequency dependence of electric field tunability in a photonic liquid crystal fiber based on gold nanoparticles-doped 6CHBT nematic liquid crystal

2020 ◽  
Vol 12 (4) ◽  
pp. 115
Author(s):  
Miłosz Chychłowski ◽  
Tomasz Woliński
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Photonic Crystal ◽  
Electric Field ◽  
External Electric Field ◽  
Photonic Crystal Fibers ◽  
Crystal Fiber ◽  
Crystal Fibers

In this paper, we investigate an external electric field frequency influence on a photonic liquid crystal fiber (PLCF) based on a gold nanoparticles (NPs)-doped nematic liquid crystal (LC) and its response to the external electric field. We used a 6CHBT nematic LC doped with 2-nm gold NPs in a weight concentration of 0.1%, 0.2%, 0.3%, and 0.5%. Full Text: PDF ReferencesJ. C. Knight, T. A. Birks, P. St. J. Russell, and D. M. Atkin, "All-silica single-mode optical fiber with photonic crystal cladding," Opt. Lett. 21, 1547-1549 (1996) CrossRef J. C. Knight,T. A. Birks, P. S. J.Russell, , and J. P. De Sandro, "Properties of photonic crystal fiber and the effective index model", JOSA A, 15(3), 748-752, (1998) CrossRef S. A. Cerqueira,F. Luan, C. M. B. Cordeiro, A. K. George, and J. C. Knight, "Hybrid photonic crystal fiber", "Optics Express", 14(2), 926-931,(2006) CrossRef W. Bragg, "Liquid Crystals", Nature 133, 445-456, (1934) https://doi.org/10.1038/133445a0 CrossRef J. Kędzierski, K. Garbat, Z. Raszewski, M. Kojdecki, K. Kowiorski, L. Jaroszewicz, and W. Piecek, "Optical properties of a liquid crystal with small ordinary and extraordinary refractive indices and small optical anisotropy", Opto-Electronics Review, 22(3), 162-165, (2014) CrossRef Y. Li, and S. T. Wu, "Polarization independent adaptive microlens with a blue-phase liquid crystal", Optics express, 19(9), 8045-8050, (2011) CrossRef T. Woliński, S. Ertman, K. Rutkowska, D. Budaszewski, M. Sala-Tefelska, M. Chychłowski, K. Orzechowski, K. Bednarska, P. Lesiak, "Photonic Liquid Crystal Fibers - 15 years of research activities at Warsaw University of Technology", Phot. Lett. Pol., (11), (2), 22-24, (2019) https://doi.org/10.4302/plp.v11i2.907. CrossRef T.T. Larsen, A. Bjraklev, D.S. Hermann, J. Broeng, Opt. Expr. 11(20), 2589, (2003) CrossRef T.R. Woliński, K. Szaniawska, K. Bondarczuk, P. Lesiak, A.W. Domański, R. Dąbrowski, E. Nowinowski-Kruszelnicki, J. Wójcik, "Propagation properties of photonic crystal fibers filled with nematic liquid crystals", Opto-Electron. Rev. 13(2), 59 (2005) DirectLink L. Scolari, S. Gauza, H. Xianyu, L. Zhai, L. Eskildsen, T. T. Alkeskjold, S.-T. Wu, and A. Bjarklev, "Frequency tunability of solid-core photonic crystal fibers filled with nanoparticle-doped liquid crystals," Opt. Express 17(5), 3754-3764 (2009). CrossRef A. Siarkowska, M. Chychłowski, D. Budaszewski, B. Jankiewicz, B. Bartosewicz, and T. R. Woliński, "Thermo-and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles", Beilstein Journal of Nanotechnology, 8(1), 2790-2801, (2017) CrossRef D. Budaszewski, M. Chychłowski, A. Budaszewska, B. Bartosewicz, B. Jankiewicz, and T. R. Woliński, "Enhanced efficiency of electric field tunability in photonic liquid crystal fibers doped with gold nanoparticles", Optics express, 27(10), 14260-14269, (2019) CrossRef D. Budaszewski, A. Siarkowska, M. Chychłowski, B. Jankiewicz, B. Bartosewicz, R. Dąbrowski, T. R. Woliński, "Nanoparticles-enhanced photonic liquid crystal fibers", Journal of Molecular Liquids, 267, 271-278, (2018) CrossRef

Acetone Sensing Based on Transmittance of Hydroxyethyl Methacrylate-Liquid Crystal Materials

2020 ◽  
Vol 840 ◽  
pp. 424-429
Author(s):  
Harry Miyosi Silalahi ◽  
Wei Fan Chiang ◽  
Chia Yi Huang
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cholesteric Liquid Crystal ◽  
Thickness Effect ◽  
Helical Axis ◽  
Hydroxyethyl Methacrylate ◽  
Absorption Process ◽  
Natural Property ◽  
Mixture Concentration

Poly hydroxyethyl methacrylate (p-HEMA) has a natural property that is very easy to absorb a liquid or solution and become a hydrogel when absorbing water. In this work, by combining p-HEMA material with a cholesteric liquid crystal (CLC), the material can absorb the solution and the optical properties of the liquid crystal will change depending on the solution it absorbs. The solution used in this work is acetone. During the absorption process the p-HEMA material expanded so that the orientation direction of liquid crystal molecular twist with a helical axis along can freely move and change. In this work, we observed the study of transmittance caused by thickness effect and the mixture concentration effect of the poly hydroxyethyl methacrylate liquid crystals (PHM-LC).

Polymer Matrix on Polymer Dispersed Liquid Crystals Electro-Optical Properties

2013 ◽  
Vol 677 ◽  
pp. 183-187
Author(s):  
Huey Ling Chang ◽  
Chih Ming Chen
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Polymer Matrix ◽  
Contrast Ratio ◽  
Butyl Methacrylate ◽  
Driving Voltage ◽  
Ethyl Methacrylate ◽  
Vis Spectroscopy ◽  
Polymer Dispersed

Polymer dispersed liquid crystal (PDLC) films are fabricated with various compositions of E7 liquid crystal (LC), 2-Hydroxy ethyl methacrylate (HEMA), Methyl methacrylate (MMA), n-butyl methacrylate (nBMA), Ethyl methacrylate (EMA), Tetraethylene glycol diacrylate (TEGDA), and Benzoin. The results show that the refractive index of the PDLC films is insensitive to the monomer side groups. The effects of different monomers addition on the microstructure, the corresponding polymer matrix motion and electro-optical properties of the PDLC samples are examined using Dynamic Mechanical Analyzers (DMA) and UV-Vis spectroscopy, respectively. The experimental results reveal that the addition of HEMA and TEGDA yields a considerable improvement in the electro-optical properties and the contrast ratio. Overall, the results show that a PDLC comprising 40wt% E7 liquid crystals, 50mol% TeGDA and 50mol% HEMA has both a high contrast ratio (12.75:1) and a low driving voltage (16 V), and is therefore a suitable candidate for smart window and a wide variety of intelligent photoelectric applications.

Infrared Microscopic Imaging of the Diffusion of Liquid Crystals into Thermoplastics

1997 ◽  
Vol 3 (S2) ◽  
pp. 841-842
Author(s):  
Bentley G. Wall ◽  
Chris M. Snively ◽  
Jack L. Koenig
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Polymer Matrix ◽  
Thermoplastic Polymer ◽  
General Direction ◽  
Display Devices ◽  
Polymer Dispersed

Thermoplastic polymer/liquid crystal systems have found application in the generation of display devices known as thermoplastic, polymer dispersed liquid crystals (PDLCs). These systems take advantage of the beneficial properties of both components to generate a device that has unique optical properties. The liquid crystal is dielectric and responds to an electric field. The polymer confines the liquid crystal so that the cells are closed. The two components are melted together until they are miscible. At lower temperatures, the two components phase separate. The liquid crystal component is the minor phase and takes the form of many tiny droplets contained within the major-phase, polymer matrix. An application of an electric field across these systems causes the liquid crystal within the droplets to align with the field. The systems are engineered such that when this alignment occurs there is no refractive index difference between the liquid crystal in the droplets and the polymer matrix, thus, the cells appear optically transparent. When there is no field applied, the liquid crystals in each droplet are aligned without respect to a general direction according to the surface energetics of each droplet/polymer interface. When this is the case, there is a refractive index mismatch between the droplets and the polymer and the cells are opaque. Research of these systems is aimed at improving the optical properties in order to facilitate the manufacturing of improved devices utilizing this technology. Because these systems are generated by a diffusion-controlled, phase separation process, understanding the relevant parameters, particularly the diffusion coefficients, should enable the manufacturing processes of these systems to be controlled more efficiently, generating improved optical properties.

scholarly journals Optical properties of metasurfaces infiltrated with liquid crystals

2020 ◽  
Vol 117 (34) ◽  
pp. 20390-20396 ◽  
Author(s):  
Andrew Lininger ◽  
Alexander Y. Zhu ◽  
Joon-Suh Park ◽  
Giovanna Palermo ◽  
Sharmistha Chatterjee ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Design ◽  
Dynamic Control ◽  
Fdtd Simulation ◽  
Optical Elements ◽  
Difference Time ◽  
Local Refractive Index

Optical metasurfaces allow the ability to precisely manipulate the wavefront of light, creating many interesting and exotic optical phenomena. However, they generally lack dynamic control over their optical properties and are limited to passive optical elements. In this work, we report the nontrivial infiltration of nanostructured metalenses with three respective nematic liquid crystals of different refractive index and birefringence. The optical properties of the metalens are evaluated after liquid-crystal infiltration to quantify its effect on the intended optical design. We observe a significant modification of the metalens focus after infiltration for each liquid crystal. These optical changes result from modification of local refractive index surrounding the metalens structure after infiltration. We report qualitative agreement of the optical experiments with finite-difference time-domain solver (FDTD) simulation results. By harnessing the tunability inherent in the orientation dependent refractive index of the infiltrated liquid crystal, the metalens system considered here has the potential to enable dynamic reconfigurability in metasurfaces.

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