title: Unconventional structure-assisted optical manipulation of high-index nanowires in liquid crystals.
abstract: Stable optical trapping and manipulation of high-index particles in low-index host media is often impossible due to the dominance of scattering forces over gradient forces. Here we explore optical manipulation in liquid crystalline structured hosts and show that robust optical manipulation of high-index particles, such as GaN nanowires, is enabled by laser-induced distortions in long-range molecular alignment, via coupling of translational and rotational motions due to helicoidal molecular arrangement, or due to elastic repulsive interactions with confining substrates. Anisotropy of the viscoelastic liquid crystal medium and particle shape give rise to a number of robust unconventional trapping capabilities, which we use to characterize defect structures and study rheological properties of various thermotropic liquid crystals.
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: David
authors.initials: D
authors.lastname: Engström
authors.forename: Michael C M
authors.initials: MC
authors.lastname: Varney
authors.forename: Martin
authors.initials: M
authors.lastname: Persson
authors.forename: Rahul P
authors.initials: RP
authors.lastname: Trivedi
authors.forename: Kris A
authors.initials: KA
authors.lastname: Bertness
authors.forename: Mattias
authors.initials: M
authors.lastname: Goksör
authors.forename: Ivan I
authors.initials: II
authors.lastname: Smalyukh
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D050866:Liquid Crystals / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D012031:Refractometry / Q000295:instrumentation*