Numerical simulation of micro- and nanoparticles orbital motion driven by an optical vortex

Micro- and nanoparticles in a solution under the irradiation of an optical vortex are considered using a mathematical model based on fluid mechanics. The particles exhibit an inherent Brownian motion due to their small sizes. In particular, we consider the case of plural particles trapped in the orbit of the optical vortex expressed by the Laguerre-Gaussian beam. The inter-particle interaction includes not only repulsive forces between the particles but also the forces arising from a hydrodynamic effect. To be more specific, the flow of a solvent induced by the motion of a particle affects the motion of the other particles. The numerical simulation of the model shows that the orbital speed of the particles increases as the number of particles in the orbit.