title: Optical conveyors: a class of active tractor beams.
abstract: We experimentally demonstrate a class of tractor beams created by coherently superposing coaxial Bessel beams. These optical conveyors have periodic intensity variations along their axes that act as highly effective optical traps for micrometer-scale objects. Trapped objects can be moved selectively upstream or downstream along the conveyor by appropriately changing the Bessel beams' relative phase. The same methods used to project a single optical conveyor can project arrays of independent optical conveyors, allowing bidirectional transport in three dimensions.
authors.affiliation: Department of Physics and Center for Soft Matter Research, New York University, New York, New York 10003, USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Ruffner
authors.forename: David G
authors.initials: DG
authors.lastname: Grier