Optical forces in a non-diffracting vortex beam

Optical force acting upon a dielectric microparticle illuminated by a non-diffracting vortex beam is expressed using the generalized Lorenz-Mie theory (GLMT). Numerical results are presented for different widths and topological charges of the vortex beam. We show that such particle may be stably trapped either in the dark center of the vortex beam, in one of the two stable positions placed off the optical axis, or as the third option it may circulate along almost circular trajectory having its radius smaller or equal to the radius of the smallest high intensity vortex ring.

► Theoretical study of optical forces based on the generalized Lorenz-Mie theory. ► Lateral behavior of polystyrene microparticle in vortex Bessel beam. ► Stable off-axis trapping without orbital motion is predicted.