Convex axicon (commonly known as cone lens or axicon prism) has a centrally outward convex surface. Its core function is to converge light rays, but unlike conventional lenses that focus to a single point, it produces an extended focal line. Generating non-diffracting beams: The most important and well-known application of convex axicons is generating nearly non-diffracting Bessel beams. During propagation, the central spot size of Bessel beams remains nearly unchanged over a long distance, and they exhibit self-healing properties.