Dynamics of microparticles trapped in a perfect vortex beam

We analyze microparticle dynamics within a “perfect ” vortex beam. In contrast to other vortex fields, for any given integer value of the topological charge, a “perfect ” vortex beam has the same annular intensity profile with fixed radius of peak intensity. For a given topological charge, the field possesses a well-defined orbital angularmomentum density at each point in space, invariant with respect to azimuthal position. We experimentally create a perfect vortex and correct the field in situ, to trap and set in motion trapped microscopic particles. For a given topological charge, a single trapped particle exhibits the same local angular velocity moving in such a field independent of its azimuthal position.We also investigate particle dynamics in “perfect ” vortex beams of fractional topological charge. This light field may be applied for novel studies in optical trapping of particles, atoms, and quantum gases. © 201