Optical trapping forces on Rayleigh particles by a focused Bessel-Gaussian correlated Schell-model beam

Zhang Hanghang, Han Yiping, Wang Jiajie, Guo Jirong

Optical trapping forces exerted by a focused Bessel-Gaussian correlated Schell-model (BGCSM) beam on Rayleigh dielectric spheres with different refractive indices are analyzed. The dependence of radiation forces on the transverse coherence width δ0, the coherence parameter β, refractive index of the particle, and particle radius are investigated. It is shown that the focused BGCSM beam can be used to trap particles with both high and low index of refraction near the focus, and as the transverse coherence width δ0 or the relative refractive indices of the particle with respect to the host medium increases, or the coherence parameter β decreases, the trapping stability increase. Furthermore, the limits of the radius for two types of particles stably captured are determined.

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