Radiation forces of a focused partially coherent flattened vortex beam on a Rayleigh spherical particle

A focused partially coherent flattened vortex beam used to trap a Rayleigh dielectric spherical particle with relative refractive index p < 1 is studied. The dependence of radiation forces (RFs) on the beam order N  , waist width w0w0, correlation length σ0, particle radius a and focal length f is analyzed and illustrated by numerical examples. By a suitable choice of N  , w0w0, σ0 and f   a stable trap of the Rayleigh particle is achievable. In particular, there exist critical values w0,cw0,c, σ0,c for a partially coherent flattened vortex beam the particle can be trapped by the beam with w0w0 less than w0,cw0,c and σ0 larger than σ0,c. A comparison with the previous work is made.