title: Trapping of single nano-objects in dynamic temperature fields.
abstract: In this article we explore the dynamics of a Brownian particle in a feedback-free dynamic thermophoretic trap. The trap contains a focused laser beam heating a circular gold structure locally and creating a repulsive thermal potential for a Brownian particle. In order to confine a particle the heating beam is steered along the circumference of the gold structure leading to a non-trivial motion of the particle. We theoretically find a stability condition by switching to a rotating frame, where the laser beam is at rest. Particle trajectories and stable points are calculated as a function of the laser rotation frequency and are experimentally confirmed. Additionally, the effect of Brownian motion is considered. The present study complements the dynamic thermophoretic trapping with a theoretical basis and will enhance the applicability in micro- and nanofluidic devices.
authors.affiliation: Molecular Nanophotonics Group, Institute of Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany. cichos@physik.uni-leipzig.de.
authors.forename: Marco
authors.initials: M
authors.lastname: Braun
authors.forename: Alois
authors.initials: A
authors.lastname: Würger
authors.forename: Frank
authors.initials: F
authors.lastname: Cichos