Stable Light Focusing by Meta-Axicons Applicable in Biosensors, Particle Trapping, Astronomical, and Imaging Devices

Axicons with the ability to convert Gaussian beams into non-diffracting Bessel beams are well-known in the field of light focusing for their large depth-of-focus. In this paper, we investigate light focusing quality of the meta-axicons in the presence of a turbulent medium in the focusing space like water and opaque obstacles in front of the axicon. We apply the required phase and amplitude profile of the axicon to a planar arrangement of meta-atoms. Dielectric c-shaped meta-atoms are designed to cover all transmitted phase and amplitude values at a wavelength of lambda = 700 nm. We show that meta-axicon's focusing parameters like its depth of focus (DOF) and its subwavelength lateral full width at half maximum (FWHM) are not affected by the presence of the turbulence in the focusing area. This effect makes meta-axicons as a promising focusing device in biosensors, telescopes, particle trapping, and imaging applications