We have considered the diffraction of the first-order Bessel beam by zone plates with two odd open Fresnel zone to generate chain-like beams with an embedded phase singularity. We have shown that the capsule size depends on the number of the second odd open Fresnel zone and the zone plate focal length. The change of the zones relative illumination leads to the change of the contrast between dark and light regions. The best contrast corresponds to the equal illumination of the zones. We have experimentally generated a chain-like beam with an embedded vortex by the first-order Bessel beam diffraction by zone plates with the first and the ninth open Fresnel zones. We experimentally proved the dislocation presence and investigated the main beam features. We demonstrated sufficiently good agreement between experimental and numerically calculated results.
Tags: bessel beam binary amplitude diffraction mask chain-like beam fresnel zones phase singularity бинарная амплитудная дифракционная маска зоны френеля пучок бесселя фазовая сингулярность цепочноподобный пучок
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