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Articles 1 - 4 of 4
Full-Text Articles in Physics
Designing Dupin Cyclides In Micro And Macro Worlds, Oleg Lavrentovich
Designing Dupin Cyclides In Micro And Macro Worlds, Oleg Lavrentovich
Oleg Lavrentovich
No abstract provided.
Chiral Symmetry Breaking By Spatial Confinement In Tactoidal Droplets Of Lyotropic Chromonic Liquid Crystals, Luana Tortora, Oleg Lavrentovich
Chiral Symmetry Breaking By Spatial Confinement In Tactoidal Droplets Of Lyotropic Chromonic Liquid Crystals, Luana Tortora, Oleg Lavrentovich
Oleg Lavrentovich
In many colloidal systems, an orientationally ordered nematic (N) phase emerges fromthe isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral polymer-crowded aqueous solutions of low-molecular weight disodium cromoglycate. The parity is broken by twisted packing of self-assembled molecular aggregates within the tactoids as manifested by the observed optical activity. Fluorescent confocal microscopy reveals that the chiral N tactoids are located at the boundaries …
Electrically Tunable Lens Based On A Dual-Frequency Nematic Liquid Crystal, Oleg Pishnyak, Susumu Sato, Oleg Lavrentovich
Electrically Tunable Lens Based On A Dual-Frequency Nematic Liquid Crystal, Oleg Pishnyak, Susumu Sato, Oleg Lavrentovich
Oleg Lavrentovich
We report on an electrically controlled liquid-crystal-based variable optical lens filled with a dual-frequency nematic material. The lens design employs a hole-patterned electrode structure in a flat nematic cell. In order to decrease the lens switching time we maximize the dielectric torque by using a dual-frequency nematic material that is aligned at an angle approximately 45 degrees with respect to the bounding plates by obliquely deposited SiOx, and by using an overdrive scheme of electrical switching. Depending on the frequency of the applied field, the director realigns either toward the homeotropic state (perpendicular to the substrates) or toward the planar …
Optical Vortices Generated By Dislocations In A Cholesteric Liquid Crystal, D. Voloschenko, Oleg Lavrentovich
Optical Vortices Generated By Dislocations In A Cholesteric Liquid Crystal, D. Voloschenko, Oleg Lavrentovich
Oleg Lavrentovich
We report the observation of optical vortices in a laser beam propagating through the stripe pattern of a cholesteric liquid crystal. The liquid crystal is confined in a cell with homogeneous boundary conditions and forms a diffraction phase grating. Optical vortices are produced by edge dislocations of the cholesteric grating. The vortices show up as spots of zero light intensity in the diffraction maxima. There is one spot in each +1 and -1 diffraction maximum and two spots in diffraction maxima +2 and -2. (C) 2000 Optical Society of America. OCIS codes: 160.3710, 050.1940, 180.1790, 070.4690.