Optically induced birefringence in dye-doped blue phase liquid crystals

2019 ◽  
Vol 46 (6) ◽  
pp. 913-919
Author(s):  
Lin ◽  
Kuo ◽  
Huang ◽  
Wu ◽  
Lin ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Pump Beam ◽  
Pump Intensity ◽  
Photoinduced Change ◽  
Methyl Red ◽  
Sem Images ◽  
Photoinduced Birefringence ◽  
Phase Liquid ◽  
Blue Phase

This paper investigates the photoinduced change of refractive index in dye (methyl red, MR)-doped blue phase (DDBP) cells by illumination of a pump beam. Through excitation of light irradiation with proper photon energy, MR can transform from trans-state to cis-state and successively diffuse and anisotropically adsorb on the inner glass substrate of the DDBP cell along the direction perpendicular to the polarisation of the pump beam. The adsorbed MR molecules can effectively rotate the orientation of the liquid crystal (LC) molecules and thereby modulate the effective refractive index of the DDBP cell. The SEM images of the adsorbed regions of the illuminated DDBP samples were also taken for discussing the relation between the pump intensity and the photoinduced birefringence.

scholarly journals Electrically-Tunable Blue Phase Liquid Crystal Microlens Array Based on a Photoconductive Film

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 65 ◽  
Author(s):  
Bing-Yau Huang ◽  
Shuan-Yu Huang ◽  
Chia-Hsien Chuang ◽  
Chie-Tong Kuo
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Electric Field ◽  
Uv Light ◽  
Focal Length ◽  
Incident Light ◽  
Microlens Array ◽  
Gradient Distribution ◽  
Phase Liquid ◽  
Blue Phase

This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive mask resulting in the variation of conductivity is adopted to produce the gradient distribution of the electric field. The reorientations of liquid crystals according to the gradient distribution of the electric field induce the variation of the refractive index. Thus, the incident light experiences the gradient distribution of the refractive index and results in the focusing phenomenon. The study investigates the dependence of lens performance on UV exposure time, the focal length of the lens, and focusing intensities with various incident polarizations. The BPLC microlens array exhibits advantages such as electrically tunability, polarization independence, and fast response time.

scholarly journals Investigation of Kerr effect in a blue phase liquid crystal using wedge-cell technique

2017 ◽  
Vol 9 (2) ◽  
pp. 54 ◽  
Author(s):  
Kamil Orzechowski ◽  
Marek Wojciech Sierakowski ◽  
Marzena Sala-Tefelska ◽  
Tomasz Ryszard Woliński ◽  
Olga Strzeżysz ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Kerr Effect ◽  
Beam Steering ◽  
Phase Liquid ◽  
Blue Phase ◽  
Blue Phases ◽  
Polymer Stabilized

In this work an alternative method for refractive index measurement of blue phase liquid crystal in the Kerr effect has been described. The proposed wedge method uses simple goniometric setup, allowing for direct index measurements for any wavelengths and index values. This is significant advantage comparing to other methods, usually having limitations of the measurement range as well as necessity complicated calculation to obtain refractive indices values. The results are reliable and agree well with the subject literature. Full Text: PDF ReferencesW. Cao et al., "Lasing in a three-dimensional photonic crystal of the liquid crystal blue phase II", Nat. Mater. 1, 111-113 (2002). CrossRef S. Meiboom, M. Sammon, W.F. Brinkman, "Lattice of disclinations: The structure of the blue phases of cholesteric liquid crystals", Phys. Rev. A. 27, 438 (1983). CrossRef S. Tanaka et al., "Double-twist cylinders in liquid crystalline cholesteric blue phases observed by transmission electron microscopy", Sci. Rep. 5, 16180 (2015). CrossRef Y. Li and S.-T. Wu, "Polarization independent adaptive microlens with a blue-phase liquid crystal", Opt. Express 19(9), 8045-8050 (2011). CrossRef N. Rong et al., "Polymer-Stabilized Blue-Phase Liquid Crystal Fresnel Lens Cured With Patterned Light Using a Spatial Light Modulator", J. of Disp. Technol. 12(10), 1008-1012 (2016). CrossRef J.-D. Lin et al., "Spatially tunable photonic bandgap of wide spectral range and lasing emission based on a blue phase wedge cell", Opt. Express 22(24), 29479-29492 (2014). CrossRef P. Joshi et al., "Tunable light beam steering device using polymer stabilized blue phase liquid crystals", Photon. Lett. Poland 9(1), 11-13 (2017). CrossRef Ch.-W. Chen et al., "Temperature dependence of refractive index in blue phase liquid crystals", Opt. Mater. Express 3(5), 527-532 (2013). CrossRef Y.-H. Lin et al., "Measuring electric-field-induced birefringence in polymer stabilized blue-phase liquid crystals based on phase shift measurements", J. Appl. Phys. 109, 104503 (2011). CrossRef J. Yan et al., "Direct measurement of electric-field-induced birefringence in a polymer-stabilized blue-phase liquid crystal composite", Opt. Express 18(11), 11450-11455 (2010). CrossRef K.A. Rutkowska, K. Orzechowski, M. Sierakowski, "Wedge-cell technique as a simple and effective method for chromatic dispersion determination of liquid crystals", Photon. Lett. Poland 8(2), 51-53 (2016). CrossRef O. Chojnowska et al., "Electro-optical properties of photochemically stable polymer-stabilized blue-phase material", J. Appl. Phys. 116, 213505 (2014). CrossRef J. Yan et al., "Extended Kerr effect of polymer-stabilized blue-phase liquid crystals", Appl. Phys. Lett. 96, 071105 (2010). CrossRef M. Chen et al., "Electrically assisting crystal growth of blue phase liquid crystals", Opt. Mater. Express 4(5), 953-959 (2014). CrossRef J. Kerr, Philos. Mag. 50, 337 (1875).

scholarly journals Low voltage and high contrast blue phase liquid crystal with red-shifted Bragg reflection

2013 ◽  
Vol 102 (1) ◽  
pp. 011113 ◽  
Author(s):  
Jin Yan ◽  
Zhenyue Luo ◽  
Shin-Tson Wu ◽  
Jyh-Wen Shiu ◽  
Yu-Cheng Lai ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Low Voltage ◽  
Bragg Reflection ◽  
High Contrast ◽  
Phase Liquid ◽  
Blue Phase

Hydrogen-bonded bent-core blue phase liquid crystal complexes containing various molar ratios of proton acceptors and donors

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 32319-32327 ◽  
Author(s):  
Chun-Chieh Han ◽  
Yu-Chaing Chou ◽  
San-Yuan Chen ◽  
Hong-Cheu Lin
Keyword(s):  
Liquid Crystal ◽  
Chain Length ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Chiral Center ◽  
Molar Ratio ◽  
Core Complex ◽  
Molar Ratios ◽  
Phase Liquid ◽  
Blue Phase

The molar ratio, alkyl chain length, lateral fluoro-substitution and the chiral center of H-bonded bent-core supramolecules would affect the BP ranges of BPLC complexes. H-bonded bent-core complex PIIIC9/AIIF* (3/7 mol mol−1) displayed the widest BPI range of ΔTBPI = 12 °C.

A Single-Cell-Gap Transflective Display Using a Blue-Phase Liquid Crystal

2011 ◽  
Vol 7 (4) ◽  
pp. 170-173 ◽  
Author(s):  
Feng Zhou ◽  
Jian-Peng Cui ◽  
Qiong-Hua Wang ◽  
Da-Hai Li ◽  
Di Wu
Keyword(s):  
Liquid Crystal ◽  
Single Cell ◽  
Phase Liquid ◽  
Blue Phase

Synthesis of chiral azobenzene derivatives and the performance in photochemical control of blue phase liquid crystal

2017 ◽  
Vol 45 (3) ◽  
pp. 370-380 ◽  
Author(s):  
Wan-Li He ◽  
Meng Li ◽  
Sheng-Qiang Liu ◽  
Mei-ju Wei ◽  
Chang Liu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Phase Liquid ◽  
Blue Phase ◽  
Azobenzene Derivatives
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