文摘
In this paper, the influence of radial step height of a spiral phaseplate on an optical diffraction structure is described. We consider a general case, when a radial step height is any rational quantity. This approach allows to investigate non-vortex and vortex beam powers dependence on this quantity. Solving the Fresnel integral, we obtain an optical on-axis intensity distribution. The presence of energy in this line indicates that a non-vortex beam component exists in the diffraction pattern. Integration results show that the power envelope of a non-vortex component is reduced with increasing of a normalized radial step height.