title: Direct observation of hydrodynamic rotation-translation coupling between two colloidal spheres.
abstract: By combining optical tweezers with polarization microscopy, the hydrodynamic coupling between position and orientation fluctuations in a pair of colloidal spheres has been measured. Imaging of birefringent particles under crossed polarizers allows for the simultaneous determination of the positions and orientations of both particles. The temporal cross-correlation function between random displacements of one particle and orientation fluctuations of its neighbor allows for the quantification of the hydrodynamic rotation-translation coupling between the spheres. Our results are in good agreement with predictions for the hydrodynamic mobility tensors calculated in the creeping-flow limit of the Navier-Stokes equation.
authors.affiliation: Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Martin
authors.forename: M
authors.initials: M
authors.lastname: Reichert
authors.forename: H
authors.initials: H
authors.lastname: Stark
authors.forename: T
authors.initials: T
authors.lastname: Gisler
mesh_terms: D001718:Birefringence; D003102:Colloids / Q000737:chemistry*; D008853:Microscopy / Q000379:methods; D008962:Models, Theoretical; D009068:Movement; D052898:Optical Tweezers; D012399:Rotation
chemical_list: D003102:Colloids