Radiation forces of focused partially coherent vortex beam acting on Rayleigh particles with different refractive indices

Radiation forces of a focused partially coherent Gaussian Schell-model (GSM) vortex beam used to trap Rayleigh dielectric spherical particles with different refractive indices are analyzed, where the dependence of radiation forces and trapping stability on the correlation length and waist width is stressed and illustrated by numerical examples. There exist critical values for the correlation length and waist width of the GSM vortex beam. The particles with relative refractive index larger than one can be trapped by the beam with waist width less than critical width or correlation length larger than critical length, while the particle with relative refractive index less than one can be trapped by the beam with waist width larger than critical width or correlation length less than critical l