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.