聚焦部分相干平顶涡旋光束对瑞利粒子的捕获

Optical trapping Rayleigh particles by a focused partially coherent flat-topped vortex beam

基于广义惠更斯-菲涅尔原理和瑞利散射理论,推导了聚焦部分相干平顶涡旋(partially coherent flat-topped vortex,PCFTV)光束作用在瑞利微粒上辐射力的表达式,主要研究聚焦PCFTV光束对不同折射率的两种粒子的捕获情况。研究结果表明,聚焦PCFTV光束可以在焦点处捕获高折射率和低折射率的粒子。随着光束阶数的增大以及相关长度的减小,光束对微粒的捕获能力增强。所得结果对PCFTV光束应用于光学操控具有一定的意义。

Based on the extended Huygens-Fresnel principle and Rayleigh scattering theory,analytical expressions of the optical radiation forces on Rayleigh dielectric spheres exerted by a focused partially coherent flat-topped vortex(PCFTV)beam are derived.The capture effect of the PCFTV beams on two kinds of particles with different refractive indices is mainly studied.The results show that the focused PCFTV beam could be adopted to capture high and low refractive index of particles near the focus.As the beam order decreases,or the correlation length increases,the ability of the beam for trapping particles increases.The results are expected to be useful for studying the trapping capacity of PCFTV beams applied in optical manipulation.