Transfer of orbital angular momentum to an optically trapped low-index particle -: art. no. 063402

We demonstrate the transfer of orbital angular momentum from a light beam to a trapped low-index particle.. The particle is trapped in a dark annular region of a high-order Bessel beam and rotates around the beam axis due to scattering from the helical wave fronts of the light beam. A general theoretical geometrical optics model. is developed that, applied to our specific situation, corroborates tweezing and transfer of orbital angular momentum to the low-index particle. Good quantitative agreement between theory and experiment for particle rotation rates is observed.