设计了一种近场涡旋光束干涉的微结构阵列。在该阵列中, 一对正交排列的矩形小孔构成阿基米德螺旋线。在线偏振太赫兹波的激励下, 其左旋和右旋分量分别形成具有异号拓扑荷数的近场涡旋光束, 并叠加产生新的电场分布。数值仿真结果表明, 通过调控每个矩形小孔的角度和螺旋线的螺距, 可实现任意拓扑荷数的正交涡旋光束的电场叠加。

A microstructural array to generate the interference of near-field vortex beams is designed, in which an Archimedean spiral line is formed by a pair of orthogonally arranged rectangular holes. Upon the excitation of a linearly polarized terahertz beam, the near field vortex beams with different topological charge numbers are formed by their left-handed and right-handed components and superimposed to generate a new field distribution. The numerical simulation results show that the field superposition of orthogonal vortex beams with arbitrary topological charge numbers can be achieved by the adjustments of the angle of each rectangular hole and the pitch of the helix.