Optical properties of a dichroic dye-doped liquid-crystal grating and its application to optical rotation measurement

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.

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Simple system for measuring optical rotation of glucose solution using liquid-crystal grating

Japanese Journal of Applied Physics ◽

10.7567/jjap.54.122601 ◽

2015 ◽

Vol 54 (12) ◽

pp. 122601 ◽

Cited By ~ 6

Author(s):

Michinori Honma ◽

Etsuo Uchida ◽

Hiroo Saito ◽

Takeshi Harada ◽

Seiei Muto ◽

...

Keyword(s):

Liquid Crystal ◽

Glucose Solution ◽

Optical Rotation ◽

Simple System ◽

Liquid Crystal Grating

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Study on the Electro-Optcial Properties of GH LCD

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.284-286.2234 ◽

2011 ◽

Vol 284-286 ◽

pp. 2234-2238

Author(s):

Rui Li Zhang ◽

Guo Ying Li ◽

Zi Qiang Huang

Keyword(s):

Optical Properties ◽

Liquid Crystal ◽

Optical Characteristic ◽

Polarized Light ◽

Characteristic Curves ◽

Dichroic Dye ◽

Orthogonal Orientation ◽

The Right ◽

First Time ◽

Cell Thickness

It’s the first time to have a research on the electro-optical properties of GH-LCD more systemic. At the beginning of the paper, the electro-optical characteristic curves have been analyzed for the different cell thickness, such as 6μm, 9μm and 11μm. The result shows that GH-LCD and TN-LCD have the similar electro-optical property, and the dichroic dye contained in the GH-LCD is the key to control the color switch. Viewing angle property in the range of ±30° was tested in the horizontal direction. The visibility of the left angle is wider than the right angel, and the contrast of the left angle is better. Then, the case that the orthogonal orientation of liquid crystal cell thickness is 11μm will be discussed in the paper. When the cell thickness is 11μm and there’s no polarizer, the electro-optical characteristic curves was measured and compared. Research shows that the polarizer can filter out polarized light to enhance contrast. The electro-optical curve with polarizer has been measured when a certain percentage of the chiral agent was added into guest-host liquid crystal (negative). When the voltage gets to 15V, there is a state of phase change that the display color immediately turns from black to milky white. Compared with liquid crystal without being added chiral material, the contrast reduces obviously, but response time becomes lower than before. The research on electro-optical properties maybe makes the GH-LCD to be applied to the naked eye 3D display.

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

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.181-182.293 ◽

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.

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