Jagodič, Uroš - Institut Jožef Stefan

Topological defect production in nematic liquid crystal with non-trivial geometry

The formation and the structure of topological defects are of great interest in various soft matter systems [1-3]. Liquid crystals exhibit universal behaviour known from cosmology to superconductivity on a scale which is observable with optical microscopy. In the experiments, we study the formation of topological defects right after sudden temperature driven symmetry breaking phase transitions [1, 4, 5], well described by the Kibble – Zurek mechanism [4, 5].

We study the production of topological defects along and in particles of non-trivial geometry dispersed in nematic and chiral nematic liquid crystal [6]. We use the process of two photon polymerization to create colloidal particles and cavities of various non-trivial geometry. The colloidal particles are placed in nematic liquid crystal with a given orientation of the director dield alon the surfaces, and filled with nematic and chiral nematic liquid crystal. We study the formation of topological defects right after sudden temperature driven symmetry breaking phase transition induced by photothermal effect. We use a modified shadowgraphy experimental set-up to study the dynamics of the system right after the dynamic freezing of the system [7]. We also use polarized fluorescence microscopy to study the stable director field configuration in and along the colloidal particles [8]. We also study the self-assembly of individual colloidal cavities of various non-trivial shape, which can be used as micro resonators for lasing. (Authors: U. Jagodič1, I. Muševič1,2. 1 Institut Jozef Stefan, Jamova 39, 1000 Ljubljana, Slovenija. 2 Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia)

Keywords: Liquid crystals, topological defects creation, Kibble – Zurek mechanism, non-trivial geometry, colloidal particles

References

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