Thermal and electrical wavelength tuning of Bragg reflection with ultraviolet light absorbers in polymer-stabilized cholesteric liquid crystals

2018 ◽  
Vol 6 (45) ◽  
pp. 12377-12385 ◽  
Author(s):  
Amid Ranjkesh ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Ultraviolet Light ◽  
Bragg Reflection ◽  
Cholesteric Liquid Crystal ◽  
Wavelength Tuning ◽  
Cholesteric Liquid Crystals ◽  
Light Absorbers ◽  
Polymer Stabilized

A dual thermal and electrical polymer-stabilized cholesteric liquid crystal has been fabricated by using ultraviolet light absorbers. The Bragg reflection can be autonomously controlled by temperature and manually by an electric field.

scholarly journals Enhanced Bandwidth Broadening of Infrared Reflector Based on Polymer Stabilized Cholesteric Liquid Crystals with Poly(N-vinylcarbazole) Used as Alignment Layer

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2238
Author(s):  
Limin Zhang ◽  
Qiumei Nie ◽  
Xiao-Fang Jiang ◽  
Wei Zhao ◽  
Xiaowen Hu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Cholesteric Liquid Crystal ◽  
Critical Role ◽  
Cholesteric Liquid Crystals ◽  
Smart Window ◽  
Alignment Layer ◽  
Thermal And Electrical Properties ◽  
Polymer Stabilized

Alignment layer plays a critical role on liquid crystal (LC) conformation for most LC devices. Normally, polyimide (PI) or polyvinyl alcohol (PVA), characterized by their outstanding thermal and electrical properties, have been widely applied as the alignment layer to align LC molecules. Here, we used a semi-conductive material poly(N-vinylcarbazole) (PVK) as the alignment layer to fabricate the cholesteric liquid crystal (CLC) device and the polymer-stabilized cholesteric liquid crystals (PSCLC)-based infrared (IR) reflectors. In the presence of ultraviolet (UV) irradiation, there are hole–electron pairs generated in the PVK layer, which neutralizes the impurity electrons in the LC–PVK junction, resulting in the reduction in the built-in electric field in the LC device. Therefore, the operational voltage of the CLC device switching from cholesteric texture to focal conic texture decreases from 45 V to 30 V. For the PSCLC-based IR reflectors with the PVK alignment layer, at the same applied electric field, the reflection bandwidth is enhanced from 647 to 821 nm, ranging from 685 to 1506 nm in the IR region, which makes it attractive for saving energy as a smart window.

scholarly journals The influence of orienting layers on blue phase liquid crystals in rectangular geometries

2018 ◽  
Vol 10 (4) ◽  
pp. 100 ◽  
Author(s):  
Marzena Maria Sala-Tefelska ◽  
Kamil Orzechowski ◽  
Filip A. Sala ◽  
Tomasz R. Woliński ◽  
Olga Strzeżysz ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Low Voltage ◽  
Bragg Reflection ◽  
Phase Liquid ◽  
Blue Phase ◽  
Blue Phases ◽  
Alignment Layers ◽  
Polymer Stabilized

In this paper, the influence of homeotropic and homogeneous orienting layers is presented in a cell filled with chiral nematic liquid crystals stabilized in a blue phase. The change of selective Bragg reflection from red to blue light was observed for homogeneous layers in rectangular geometries. The growth of blue phase crystals domains in a glass cell as well an influence of temperature and the electric field on such a structure, are also presented. Full Text: PDF ReferencesF. Reinitzer, Beitrage zur Kenntniss des Cholestherins, Monatsh Chem. 9, 421-441, (1888). CrossRef J. Yan, M. Jiao, L. Rao, and S.-T. Wu, "Direct measurement of electric-field-induced birefringence in a polymer-stabilized blue-phase liquid crystal composite", Opt. Express 18, 11450-11455 (2010) CrossRef Y. Chen, D. Xu, S.-T. Wu, S.-i. Yamamoto, Y. Haseba, "A low voltage and submillisecond-response polymer-stabilized blue phase liquid crystal", Appl. Phys. Lett. 102, 141116 (2013) CrossRef Y. Huang, H. Chen, G. Tan, H. Tobata, S. Yamamoto, E. Okabe, Y.-F. Lan, C.-Y. Tsai, and S.-T. Wu, "Optimized blue-phase liquid crystal for field-sequential-color displays", Opt. Mater. Express 7, 641-650 (2017) CrossRef V. Sridurai, M. Mathews, C. V. Yelamaggad, G. G. Nair, "Electrically Tunable Soft Photonic Gel Formed by Blue Phase Liquid Crystal for Switchable Color-Reflecting Mirror", ACS Appl. Mater. Interfaces, 9 (45), 39569-39575 (2017) CrossRef E. Oton, E. Netter, T. Nakano, Y. D.-Katayama, F. Inoue, "Monodomain Blue Phase Liquid Crystal Layers for Phase Modulation", Sci. Rep. vol.7, 44575 (2017) CrossRef Q. Liu, D. Luo, X. Zhang, S. Li, Z. Tian, "Refractive index and absorption coefficient of blue phase liquid crystal in terahertz band", Liq. Cryst., Vol. 44, No. 2, pp. 348-354 (2017) CrossRef Y. Li, Y. Liu, Q. Li, S.-T. Wu, "Polarization independent blue-phase liquid crystal cylindrical lens with a resistive film", Appl. Opt., Vol. 51, No. 14, pp. 2568-2572 (2012) CrossRef M. M. Sala-Tefelska, K. Orzechowski M. Sierakowski, A. Siarkowska, T.R. Woliński, O. Strzeżysz, P. Kula, "Influence of cylindrical geometry and alignment layers on the growth process and selective reflection of blue phase domains", Opt. Mater. 75, 211-215, (2018) CrossRef H. Claus, O. Willekens, O. Chojnowska, R. Dąbrowski, J. Beeckman, K. Neyts, "Inducing monodomain blue phase liquid crystals by long-lasting voltage application during temperature variation", Liq. Cryst. 43 (5), 688-693, (2016) CrossRef M. Takahashi, T. Ohkawa, H. Yoshida, J. Fukuda, H. Kikuchi, M. Ozaki, "Orientation of liquid crystalline blue phases on unidirectionally orienting surfaces", J. Phys. D: Appl. Phys. 51 (10), 104003 (2018) CrossRef P. Joshi, X. Shang, J. De Smet, E. Islamai, D. Cuypers, G. Van Steenberge, S. Van Vlierberghe, P. Dubruel, H. De Smet, "On the effect of alignment layers on blue phase liquid crystals", Appl. Phys. Lett. 106, 101105 (2015) CrossRef K. Orzechowski, M.W. Sierakowski, M. Sala-Tefelska, P. Joshi, T.R. Woliński, H.D. Smet, "Polarization properties of cubic blue phases of a cholesteric liquid crystal", Opt. Mater. 69, 259-264 (2017) CrossRef P.-J. Chen, M. Chen, S.-Y. Ni, H.-S. Chen, Y.-H. Lin, "Influence of alignment layers on crystal growth of polymer-stabilized blue phase liquid crystals", pt. Mater. Express 6, 1003-1010 (2016) CrossRef CrossRef

scholarly journals The Propagation of the Electromagnetic Wave in Multilayers Structures Composed from Cholesteric Liquid Crystals under the Influence of the External Electric Field

2009 ◽  
Vol 19 (1) ◽  
pp. 26-32
Author(s):  
Pho Thi Nguyet Hang ◽  
Pham Thuy Dung
Keyword(s):  
Electromagnetic Wave ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
External Electric Field ◽  
Reflection Spectrum ◽  
Cholesteric Liquid Crystal ◽  
Incident Beam ◽  
Multilayer Structures ◽  
Cholesteric Liquid Crystals

The tensor solution for the electromagnetic wave being in quadrature with the surface of the cholesteric liquid crystal under the influence of the external electric field along axis of swing of crystal, has been found. Description of the reflection, transmission of the electromagnetic wave in multilayer structures composed from cholesteric liquid crystals have been shown. Futher the dependence of the reflection spectrum on the polarization of the incident beam and magnitude of the external electric field are determined.

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 Fabrication of multicolored patterns based on dye-doped cholesteric liquid crystals

2019 ◽  
Vol 18 (7) ◽  
pp. 1638-1648 ◽  
Author(s):  
Linlin Xu ◽  
Hanbing Zhang ◽  
Jie Wei
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Fluorescence Enhancement ◽  
Cholesteric Liquid Crystal ◽  
Cholesteric Liquid Crystals ◽  
Dual Mode

We developed a type of dye-doped cholesteric liquid crystal, which were used for fluorescence enhancement and dual-mode multicolor patterns.

scholarly journals Applications of Natural Purple from Dolabella auricularia: Colouration of Cholesteric Liquid Crystals

2016 ◽  
Vol 50 ◽  
pp. 1-6
Author(s):  
Yuki Kudo ◽  
Hiromasa Goto
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cholesteric Liquid Crystal ◽  
Optical Microscope ◽  
Hydroxypropyl Cellulose ◽  
Cholesteric Liquid Crystals ◽  
Optical Texture ◽  
Sea Hare ◽  
Crystal Mixture

Hydroxypropyl cellulose (HPC) as a cholesteric liquid crystal was coloured with purple ink from Dolabella auricularia as a sea hare. Optical texture of the liquid crystal mixture was confirmed with a polarising optical microscope.

Electrically tunable infrared reflector with adjustable bandwidth broadening up to 1100 nm

2016 ◽  
Vol 4 (16) ◽  
pp. 6064-6069 ◽  
Author(s):  
Hitesh Khandelwal ◽  
Michael G. Debije ◽  
Timothy J. White ◽  
Albertus P. H. J. Schenning
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ethylene Glycol ◽  
Cholesteric Liquid Crystals ◽  
Anisotropic Liquid ◽  
Polymer Stabilized ◽  
Bandwidth Broadening

A tunable infrared reflector has been fabricated using polymer stabilized cholesteric liquid crystals containing a negative dielectric, anisotropic liquid crystal and a long and flexible ethylene glycol twin crosslinker.

scholarly journals Nanoscale hyperspectral imaging of tilted cholesteric liquid crystal structures

Soft Matter ◽  
2019 ◽  
Vol 15 (15) ◽  
pp. 3256-3263 ◽  
Author(s):  
Aurélie Jullien ◽  
Adriana Scarangella ◽  
Umberto Bortolozzo ◽  
Stefania Residori ◽  
Michel Mitov
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Crystal Structures ◽  
Hyperspectral Imaging ◽  
Spectral Properties ◽  
Cholesteric Liquid Crystal ◽  
Cholesteric Liquid Crystals

In tilted cholesteric liquid crystals, hyperspectral imaging reveals the correlation between the bandgap spectral properties and spatial twists.

Frustrated Structures and Pattern Formation After Thermal Quenches in Cholesteric Liquid Crystal Droplets

2021 ◽  
Author(s):  
Renan Biagio ◽  
Rodolfo Teixeira de Souza ◽  
Luiz Roberto Evangelista ◽  
Rafael S Zola
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Pattern Formation ◽  
Condensed Matter ◽  
Cholesteric Liquid Crystal ◽  
Layered Structures ◽  
Soft Condensed Matter ◽  
Cholesteric Liquid Crystals ◽  
Spherical Droplets ◽  
Complex Arrangement

The complex arrangement of layered structures in curved geometries is a ubiquitous problem in soft condensed matter systems. In general, cholesteric liquid crystals (CLCs) in spherical droplets have been studied...

Tunable Optical Filter with Variable Bandwidth Based on Cholesteric Liquid Crystal

2011 ◽  
Vol 181-182 ◽  
pp. 273-276
Author(s):  
Shi Chao Zhang ◽  
Yu Hua Huang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Incident Light ◽  
Cholesteric Liquid Crystal ◽  
Optical Filter ◽  
Tunable Filter ◽  
Cholesteric Liquid Crystals ◽  
Central Wavelength ◽  
Variable Bandwidth ◽  
Tunable Optical Filter

An optical tunable filter with variable bandwidth has been demonstrated using two cholesteric liquid crystals. The incident light was first reflected by the first cholesteric liquid crystal and then by the second one. By rotating the two cholesteric liquid crystals simultaneously, the central wavelength can be tuned. By fixing one of the cholesteric liquid crystals and rotating the other one, the bandwidth of the tunable filter can be varied. The central wavelength of the tunable optical filter can be tuned from 513.4 nm to 576.8 nm and the bandwidth is varied from 10 nm to 80 nm. This property will allow it to be widely used in many fields, including optical communications and multispectral and hyperspectral imaging systems.

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