基于圆锥透镜生成双级无衍射光束的理论分析

为进一步完善多级无衍射光束的传输与转换理论，基于轴锥镜法和菲涅耳衍射理论对双级无衍射光束的光场分布做了详细理论分析，采用数值模拟软件对双级无衍射光束的空间光强分布与轴上光强分布进行仿真；基于锥镜加工工艺对锥镜顶点和一、二级锥镜临界点呈双曲线分布的双级轴棱锥透镜的光场分布进行研究，分析了双级无衍射光场的场强大小和影响光场振荡周期的因素。结果表明:理想双级轴棱锥透镜生成的无衍射光场由4个区域组成，在干涉重合区其光强为一、二级轴棱锥衍射场的耦合叠加，其余区域仍保持单级无衍射光场分布特性；锥镜顶点和一、二级锥镜临界点呈双曲线分布的双级轴棱锥透镜的光场分布受双曲线特征参数影响较大。其特殊的光场分布为多级无衍射光束拓展至大尺寸空间测量以及粒子微操作等提供了新的可能。

Theoretical analysis of generating two-stage non-diffracting beam based on axicon method

In order to further complete the transmission and transformation theory of multilevel non-diffracting beam, the light field distribution of two-stage non-diffracting beam was analyzed detailed based on axicon method and Fresnel diffraction theory. Firstly, the distribution of spatial light intensity and axial light intensity was simulated by numerical simulation software. At the same time, the influence of processing technology on the light distribution of the two-stage axicon with the hyperbolic contours on the vertex of the axicon and the critical point of one/two stage axicon was investigated. Then the influencing factors on the field intensity and the oscillation period of the light field were analyzed. The results show that the diffraction light field generated by the ideal two-stage axicon is composed of 4 regions. In the interference overlap zone, the intensity is the coupling superposition of the diffraction field of the one/two stage axicon, and the other regions still maintain the single-stage non-diffracting light field distribution, while for the two-stage axicon with the hyperbolic contours on the vertex of the axicon and the critical point of one/two stage axicon, the light field distribution is greatly affected by hyperbolic characteristic parameters.Its special light field distribution provides new possibilities for expanding multi-level non-diffracting beam to large-scale space measurement and particle micro-operation.