title: Topological switching and orbiting dynamics of colloidal spheres dressed with chiral nematic solitons.
abstract: Metastable configurations formed by defects, inclusions, elastic deformations and topological solitons in liquid crystals are a promising choice for building photonic crystals and metamaterials with a potential for new optical applications. Local optical modification of the director or introduction of colloidal inclusions into a moderately chiral nematic liquid crystal confined to a homeotropic cell creates localized multistable chiral solitons. Here we induce solitons that "dress" the dispersed spherical particles treated for tangential degenerate boundary conditions, and perform controlled switching of their state using focused optical beams. Two optically switchable distinct metastable states, toron and hopfion, bound to colloidal spheres into structures with different topological charges are investigated. Their structures are examined using Q-tensor based numerical simulations and compared to the profiles reconstructed from the experiments. A topological explanation of observed multistability is constructed.
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
authors.forename: T
authors.initials: T
authors.lastname: Porenta
authors.affiliation: 1] Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia [2] J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia [3] Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104, USA.
authors.forename: S
authors.initials: S
authors.lastname: Copar
authors.affiliation: 1] Department of Physics, University of Colorado, Boulder, CO 80309, USA [2] Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Ackerman
authors.affiliation: Department of Physics, University of Colorado, Boulder, CO 80309, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Pandey
authors.affiliation: Department of Physics, University of Colorado, Boulder, CO 80309, USA.
authors.forename: M C M
authors.initials: MC
authors.lastname: Varney
authors.affiliation: 1] Department of Physics, University of Colorado, Boulder, CO 80309, USA [2] Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309, USA [3] Liquid Crystal Materials Research Center and Materials Science and Engineering Program, University of Colorado, Boulder, CO 80309, USA [4] Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, CO 80309, USA.
authors.forename: I I
authors.initials: II
authors.lastname: Smalyukh
authors.affiliation: 1] Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia [2] J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: S
authors.initials: S
authors.lastname: Žumer