Linearly polarized ultraviolet photoreaction of photocrosslinkable polymers comprising thep-phenylenediacrylate group and photoalignment control of liquid crystals on the resultant film

Author(s):  
Nobuhiro Kawatsuki ◽  
Imin Sai ◽  
Tohei Yamamoto
2004 ◽  
Vol 59 (7-8) ◽  
pp. 510-516 ◽  
Author(s):  
Ewa Chrzumnicka ◽  
Mirosław Szybowicz ◽  
Danuta Bauman

The orientational behaviour of some liquid crystals with various molecular structures was studied by means of the Raman scattering depolarization method. The Raman scattering spectra of linearly polarized light were recorded as a function of temperature in the nematic phase. On the basis of these spectra the order parameters 〈P2〉 and 〈P4〉 as well as the molecular distribution function were determined. The obtained data were compared with those estimated on the basis of polarized light absorption and emission measurements. The influence of the molecular structure on the orientational order of liquid crystals was discussed.


2020 ◽  
Vol 54 (1 (251)) ◽  
pp. 56-60
Author(s):  
H.H. Hovakimyan

In this work we study the propagation of light in a twist-oriented pleochroic nematic liquid crystal with pleochroic dye. The dependence of the intensity of transmitted light on the azimuthal angle of the linearly polarized incoming light has been investigated experimentally. As a result, the role of absorption anisotropy has been identified.


Author(s):  
Helen F Gleeson ◽  
Tiffany A Wood ◽  
Mark Dickinson

Laser trapping of particles in three dimensions can occur as a result of the refraction of strongly focused light through micrometre-sized particles. The use of this effect to produce laser tweezers is extremely common in fields such as biology, but it is only relatively recently that the technique has been applied to liquid crystals (LCs). The possibilities are exciting: droplets of LCs can be trapped, moved and rotated in an isotropic fluid medium, or both particles and defects can be trapped and manipulated within a liquid crystalline medium. This paper considers both the possibilities. The mechanism of transfer of optical angular momentum from circularly polarized light to small droplets of nematic LCs is described. Further, it is shown that droplets of chiral LCs can be made to rotate when illuminated with linearly polarized light and possible mechanisms are discussed. The trapping and manipulation of micrometre-sized particles in an aligned LC medium is used to provide a measure of local shear viscosity coefficients and a unique test of theory at low Ericksen number in LCs.


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