Generation of non-diffractive Lommel beams based on all-dielectric metasurfaces

Lommel beam is a non-diffractive vortex beam of high concern recently, widely used in communication and turbulence studies. However, conventional methods of generating Lommel beams, such as using spatial light modulators (SLMs), are limited by their low resolution, poor phase manipulation, and small numerical aperture (NA). Here, non-diffractive Lommel beams based on all-dielectric metasurfaces are proposed. Using the Pancharatnam-Berry (PB) phase arrangement, the focal depth of the main lobe of the generated beam can reach 75 mu m (similar to 119 lambda). Additionally, the broadband characteristics of the designed metasurface between 550 and 710 nm are observed. The resulting beam is demonstrated to show excellent self-healing properties by placing up obstacles. We also combine the phase of the Dammann grating with that of the Lommel beam to create a metasurface capable of producing a 1 x 4 Lommel beam array; the generated beams are still characterized by uniformity and non-diffraction. This study provides a new idea for Lommel beam generation with promising applications in optical communication, optical tweezers, and laser fabrication. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This study introduces a method for generating non-diffractive Lommel beams based on all-dielectric metasurfaces, with good focal depth and broadband characteristics, demonstrating excellent self-healing properties. By combining the phase of the Dammann grating, a metasurface capable of producing a Lommel beam array is successfully created.