title: Single-particle colloid tracking in four dimensions.
abstract: Coating a close-packed fluorescent colloid monolayer with a nanometer-thick metal film followed by sonication in liquid produces modulated optical nanoprobes. The metal coating modulates the fluorescence as these structures rotate in suspension, enabling the use of these particles as probes to monitor both rotational and center-of-mass (translational) dynamics in complex environments. Here, we demonstrate methods to simultaneously measure two translational and two rotational degrees of freedom, with excellent agreement to theory. The capability to determine two angles of rotation opens several new avenues of future research.
authors.affiliation: Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Anthony
authors.forename: Liang
authors.initials: L
authors.lastname: Hong
authors.forename: Minsu
authors.initials: M
authors.lastname: Kim
authors.forename: Steve
authors.initials: S
authors.lastname: Granick