## Abstract

We study the effect on a Brownian particle (2 μm diameter polystyrene sphere in water) of an infrared optical tweezer moving in a circle. For a given potential depth of the optical trap, three different regimes for the particle motion are observed as a function of the trap velocity. For small velocity of the tweezer (typically <100 μm/s), the particle is trapped and moves with the beam. For intermediate velocities (between 100 μm/s and 3 mm/s), the particle escapes but is caught by the returning trap: its mean angular velocity scales asymptotically as the inverse of the trap rotation frequency. For large tweezer velocities (>3 mm/s), the particle diffuses along the circle but is confined in the radial direction. We describe these observations by a simple deterministic model. We justify the use of this model solving the corresponding Fokker-Planck equation.

Original language | English |
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Pages (from-to) | 5239-5250 |

Number of pages | 12 |

Journal | Physical Review E |

Volume | 51 |

Issue number | 6 |

DOIs | |

State | Published - 1995 |

Externally published | Yes |