A magneto-optic trap for micro-objects is described. Magnetic beads were trapped by optical tweezers while being rotated by a new integrated magnetic manipulator. Rotation was achieved with eight electromagnets with tip-pole geometry. The time orbital potential technique was used to achieve rotation of magnetic beads. Trapping in three dimensions and rotation of magnetic beads on three axes are demonstrated with forces up to 230 pN and force momenta of up to 10-16N m . A position-detection apparatus based on an interferometric scheme provides nanometer sensitivities in a few milliseconds.
© 2001 Optical Society of America
(140.7010) Lasers and laser optics : Laser trapping
(170.1420) Medical optics and biotechnology : Biology
(230.3810) Optical devices : Magneto-optic systems
(230.5440) Optical devices : Polarization-selective devices
L. Sacconi, G. Romano, R. Ballerini, M. Capitanio, M. De Pas, M. Giuntini, D. Dunlap, L. Finzi, and F. S. Pavone, "Three-dimensional magneto-optic trap for micro-object manipulation," Opt. Lett. 26, 1359-1361 (2001)