We report the light beam action on the nematic liquid crystal film with a free surface. It was found that a weak light absorption by the liquid crystal substrate dramatically changes the orienting properties of the light beam; in particular, a thermal gradient field induces an umbilical defect formation.

Dye-doped nematic liquid-crystalline polymers exhibit much higher orientational optical response than the systems based on low-molar-mass liquid crystals. In addition, polymer materials possess the glassy state, which allows one to record their supramolecular structure. We study the effect of light field inhomogeneity on the director deformation in the geometry of Fréedericksz transition and recording of corresponding phase structures. The relationship of the light beam width with the threshold light intensity and the size of the induced and recorded deformation region was determined. An influence of the beam waist radius on the polymer director relaxation time was detected. The results of numerical calculations based on the continuum theory and the independence of the enhancement factor of the optical torque on light–polymer interaction geometry agree with the experimental data.

Laser beam propagation through and absorption in composite and anisotropic media is simulated by solving numerically Maxwell’s equations with the FDTD method. Laser treatment of materials, light beam transformation in micron-sized optical fiber systems and liquid crystalline materials, generation of optical vortices (beams with non-zero orbital angular momentum) due to interaction with liquid crystal disclinations are considered. Typical grids used for simulations consist of tens and hundreds of millions of cells. The numerical code is parallelized using geometrical domain decomposition and the MPI library for data transfer between nodes of a computational cluster.

Laser beam propagation through an integrated fiber-optical system including a miniature cavity filled with a liquid crystal (LC) is numerically simulated. Two different shapes of the cavity are considered: a transverse cylindrical hole and a gap between the parallel end faces of the optical fiber. In both cases, the director field distribution in the LC volume includes a linear singularity (disclination). The Maxwell equations for an anisotropic continuous medium are solved by the FDTD method. Nonlinear effects of beam interaction with the LC medium are ignored. The simulations provide the data on the intensity distribution and direction of the laser beam that passed through the microscopic LC volume. The portions of laser radiation lost due to scattering into the ambient medium and remaining inside the optical fiber are calculated. Based on the calculations, it may be concluded that a significant fraction of the beam energy in the case with the cavity shaped as a transverse hole is scattered owing to focusing and diffraction induced by surface curvature and the finite transverse size of the hole. Moreover, there are regions with elevated energy density in the optical fiber behind the hole, which may lead to fiber fracture under the ultimate load possible in the pulsed mode. In contrast to the system with a hole, the deflection of beam propagation from a straight line in the fiber-optical system with a gap is fairly small. It is noted that beam-LC interaction can lead to the emergence of new fiber-optical modes in the transmitted beam.

Light beam propagation through an anisotropic liquid crystal medium is numerically simulated. The Maxwell equations are solved by the FDTD method on computational grids with up to 6 . 10(8) nodes. Propagation of the fundamental mode HE11 of the fiber-optical light guide through a layer of a nematic liquid crystal filling a transverse gap in the optical fiber and containing a disclination. The behavior of the angular moment as a function of the layer thickness and disclination power is studied. System parameters that ensure the most effective generation of twisted light beams are found.

The paper describes the technology of ultra-fine powder production; the powder consists of plastic spherical microcapsules containing a liquid crystal. The average size of the capsules is about ~ 10 micrometers, wall thickness ~ 0.1 micrometer. Some electrooptical properties of the produced microcapsules have been studied. It is proposed to use these microcapsules to manufacture flexible film liquid-crystal indicators. Despite evident advantages, the polymer-dispersed liquid crystals (PDLC) still have not been widely spread due to a number of technological problems. We suppose some of these problems can be solved with the aid of a microencapsuling (MC) technology, i. e. the manufacturing of disperse polymer microcapsules filled with the liquid crystal (LC), followed with the production polymer films based on them. The microencapsulating improves significantly the technological and functional properties of various products and considerably widens the area of their application. With the aid of this technology, many challenges can be solved, for example, the toxicity and volatility of the products can be decreased, density can be changed, color, odor, and taste can be hidden, and the content of the MC core can be protected from the ambient action (1). That is why at the very beginning of the PDLC investigations, some authors tried (2) to use this technology to produce the PDLC. The method of this task solution on the state-of-the-art technological level is described below.