Dynamic trapping and release of multiple particles in a polarized optical vortex

We calculate rigorously the optical forces on two interacting particles trapped in an optical vortex with helical phase front and demonstrate the dynamic process of the two particles' evolution. We show that in this two-particle system, a particle trapped by an optical vortex at one moment can be released due to the interaction from the other trapped particle in the next moment. To our best knowledge, this work is the first theoretical description on dynamic evolution of multiple particles trapped by an optical vortex.