Multilevel Spiral Axicon for High-Order Bessel-Gauss Beams Generation

This paper presents an efficient method to generate high-order Bessel-Gauss beams carrying orbital angular momentum (OAM) by using a thin and compact optical element such as a multilevel spiral axicon. This approach represents an excellent alternative for diffraction-free OAM beam generation instead of complex methods based on a doublet formed by a physical spiral phase plate and zero-order axicon, phase holograms loaded on spatial light modulators (SLMs), or the interferometric method. Here, we present the fabrication process for axicons with 16 and 32 levels, characterized by high mode conversion efficiency and good transmission for visible light (lambda = 633 nm wavelength). The Bessel vortex states generated with the proposed diffractive optical elements (DOEs) can be exploited as a very useful resource for optical and quantum communication in free-space channels or in optical fibers.

Automated summary

This paper proposes an efficient method to generate high-order Bessel-Gauss beams with orbital angular momentum (OAM) using a thin and compact optical element such as a multilevel spiral axicon. This approach provides a diffraction-free alternative to complex methods for OAM beam generation. The fabrication process for axicons with 16 and 32 levels is presented, which exhibit high mode conversion efficiency and good transmission for visible light. The Bessel vortex states generated by the proposed diffractive optical elements (DOEs) can be utilized for optical and quantum communication in free-space channels or optical fibers.