Phys. Rev. Lett. 101, 128301 (2008) [4 pages]Influence of Nonconservative Optical Forces on the Dynamics of Optically Trapped Colloidal Spheres: The Fountain of ProbabilityReceived 10 December 2007; revised 4 April 2008; published 16 September 2008 We demonstrate both experimentally and theoretically that a colloidal sphere trapped in a static optical tweezer does not come to equilibrium, but rather reaches a steady state in which its probability flux traces out a toroidal vortex. This nonequilibrium behavior can be ascribed to a subtle bias of thermal fluctuations by nonconservative optical forces. The circulating sphere therefore acts as a Brownian motor. We briefly discuss ramifications of this effect for studies in which optical tweezers have been treated as potential energy wells. © 2008 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.101.128301
DOI:
10.1103/PhysRevLett.101.128301
PACS:
82.70.Dd, 87.80.Cc
|
|
About | Terms and Conditions | Subscriptions | Search | Help
Use of the American Physical Society websites and journals implies that the user has read and agrees to our Terms and Conditions and any applicable Subscription Agreement. Physical Review®, Physical Review Letters®, Reviews of Modern Physics®, and Physical Review Special Topics® are trademarks of the American Physical Society.