Trapping two types of particles using a focused partially coherent elegant Laguerre–Gaussian beam

Chengliang Zhao and Yangjian Cai

The radiation forces on a Rayleigh dielectric sphere induced by a focused partially coherent elegant Laguerre–Gaussian (ELG) beam are investigated by using the Rayleigh scattering theory. It is found that a focused partially coherent ELG beam with suitable mode orders can be used to trap a Rayleigh particle whose refractive index is larger or smaller than that of the ambient by varying its initial spatial coherence width. Therefore, one can use one optical–trap system to trap two types of particles with different refractive indices.

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