高数值孔径聚焦系统中的光学参量对三维双光链的影响

Influence of Optical Parameters of High Numerical Aperture Focusing System on Three-Dimensional Twin-Optical Chain

设计了衍射光学元件,利用该元件对入射的角向偏振拉盖尔-高斯矢量光束进行调制,在高数值孔径聚焦透镜的焦平面附近获得了沿光轴方向成对的三维多点光俘获结构——双光链。分析了入射光束的参数(缔合拉盖尔多项式的拓扑荷数和径向模数以及光束的拦截比)、衍射光学元件的内外环结构和聚焦透镜的数值孔径对双光链的影响。结果表明,改变拓扑荷数和径向模数会破坏双光链结构,通过调节拦截比和衍射光学元件的结构可重新获得双光链,从而实现对双光链结构的高自由度控制。

A diffractive optical element is designed, and the element can be used to modulate the incident azimuthally polarized Laguerre-Gaussian vector beam. A three-dimensional multipoint optical trapping structure （twin-optical chain） is obtained along optical axis near the focal plane of high numerical aperture focusing lens. The effects of the parameters of incident beam （the topological charge and the radial mode number of associated Laguerre polynomial and the interception ratio of incident beam）, the structures of inner and outer rings of the diffractive optical element, and the numerical aperture of the focusing lens on the twin-optical chain are analyzed. Results show that the structure of twin-optical chain is destroyed when we change the topological charge and the radial mode number, the twin-optical chain can be obtained again when we adjust the interception ratio and the structure of the diffractive optical element, and the high degree of freedom control of the twin-optical chain can be achieved.