Optical trapping of Rayleigh particles based on four-petal Gaussian vortex beams.

The intensity distribution of four-petal Gaussian vortex (FPGV) beams through a focused optical system and the radiation force acting on a Rayleigh dielectric sphere is obtained based on the extended Huygens-Fresnel principle and the Rayleigh scattering theory. We mainly study the trapping of high and low refractive index Rayleigh particles by FPGV beams and the effect of the topological charge m on the radiation force. The results show that the specific distribution of the incident beam can be controlled by a reasonable choice of topological charge m. The multiple locations in a beam of light where particles of different refractive indices can be captured will be found. On the other hand, when m changes, the number of particles captured and the locations where they can be captured change accordingly. Therefore, the flexibility to simultaneously capture multiple Rayleigh particles with different refractive indices with a single beam at different locations in the focal plane can be achieved using the FPGV beam.