Tight focusing of a quasi-cylindrical optical vortex

In this article, we numerically investigate the tight focusing of a quasi-cylindrical optical vortex with azimuthal polarization and a wavelength of 532 nm using a Fresnel zone plate with a numerical aperture of NA = 0.95. It is shown that the focal spot produced by a beam with six sectors does not differ from the ideally azimuthally polarized optical vortex; a difference in the focal spot diameter does not exceed 0.001 of the wavelength.