基于双环形旋涡相位调制的多焦点产生

为提高光学显微成像及微粒控制的效率,提出一种通过双环形旋涡相位板对入射光为拉盖尔高斯柱矢量光束进行波前相位调制的多焦点产生方法。通过Debye矢量衍射理论分析了该相位板对焦点区域光强分布的影响。分析表明,经调节内外环旋涡相位拓扑数及内环的半径,可以对焦点区域光强分布进行整形,在焦平面上产生多焦点,而且通过改变入射柱矢量光束的偏振态,可以进一步得到光场由轴向分量为主的多焦点及由横向分量组成的多焦点。通过改变旋涡相位板的拓扑数及光束的参数,可以达到对光斑的数量的控制。这对于捕捉折射率高于周围环境折射率的微粒具有重要的应用价值。

Multi-focal spots formed by the modulation of double ring-shape vortex phase plate

To enhance the efficiency of optical imaging and particles manipulation, a novel method is proposed to form the multi-focal spots by focusing Laguerre-Gaussian cylindrical vector beam and the modulation of double ring shape vortex phase plate. Based on the Debye vectorial theory, the influence of this phase plate to the focal light intensity is investigated. By adjusting the radius and topological numbers of the inner and outer ring, the light intensity distribution in the focal region can be reshaped. Multi-focal spots are generated in the focal plane. Moreover, by changing the polarization state of incident cylindrical vector beam, the focal light intensity of the multi-focal spots with major longitudinal component and transverse component are obtained. The number of spots formed in the focal region is determined by the topological numbers of the inner and outer ring. In the field of particle manipulation, several particles can be trapped at a time in multi-focal spots, which could enhance the efficiency of particles trapping and has great practical value in trapping particles with the refractive index larger than that of the surrounding medium.