Diffraction by Cantor fractal zone plates

Abstract

The paper reports studies, both experimental and using numerical simulation, of the Fresnel diffraction by recently introduced fractal zone plates associated with triadic and quintic Cantor sets. The evolution of the intensity patterns at planes transversal to the propagation direction is presented. A series of conventional and doughnut-like foci are observed around the principal focus. The position, depth and size of the foci depend on similarity dimensions and the fractal level of the encoded fractal structures, both directly related to the number of the corresponding Fresnel zones.