Numerical Modeling of Singular Beam Evolution Diffracted on Surface Periodic Inhomogeneities

In this paper, we used a numerical model to study the diffraction of scalar beams reflected from surfaces with rectangular periodic relief. We qualitatively analyzed the evolution of phase singularities in vortex beams with single and double topological charges. The influence of the relief depends on its height and position relative to the beam axis. It was shown that the magnitude of distortions in the initial beam increased when the ratio of the depression to the overhang became smaller than the radius of the singular beam on the surface of the specimen under study, whose relief height did not exceed one-quarter of the wavelength.