Radiation forces on a dielectric sphere produced by highly focused hollow Gaussian beams

The radiation force on a dielectric sphere produced by highly focused hollow Gaussian beams (HGBs) in the Rayleigh scattering regime is theoretically investigated. Numerical results demonstrate that, the highly focused HGB at the focus of the lens system becomes a peak-centered shape which can be used to stably trap and manipulate the particles with the refractive index larger than the ambient, and in the neighborhood of the focus the beam becomes a doughnut shape which can be used to guide the particles with refractive index lower than the ambient. The condition of the trapping stability is also analyzed.