The sub-wavelength complex micro-axicons for focal spot size reducing using high-performance computer systems

The numerical studies of laser radiation focusing by the complex subwavelength diffractive axicons with different relief heights and refractive indices of axicon rings in the near zone are carried out in this paper (3D propagation). The Super- Gauss and an optical vortex with circular polarization were considered as the input laser radiation. It should be noted that the change in the height and refractive index of the relief of the optical elements made it possible, in the general case, to obtain better focusing in comparison with a conventional diffractive axicon with the same numerical aperture. In particular, it turned out to reduce the focal spot size by 15 percent for the case of an optical vortex.