3D printed photonic structure for generation to zeroth- and high-order Bessel beams from a single-mode optical fiber

Bessel beams have gained prominence due to their diffraction-free propagation and self-healing properties [1] . The zeroth-order Bessel beam has maximum intensity at its center and has found many applications, including optical trapping and bio-imaging. On the other hand, higher-order Bessel beams have a node due to a phase singularity and carry orbital angular momentum (OAM). Over the past years, Bessel beams have been generated by using different approaches, namely by Fourier transforming a narrow circular beam with a lens, by using axicons and with holographic beam shaping techniques. The need to miniaturize optics has led to efforts towards the on-fiber generation of Bessel beams. The successful attempts include the fabrication of a customized annular-core fiber along with a polymer lens [2] , or modifying the end of the fiber to an axicon profile with chemical or lithographic methods [3] . These techniques have limited capability on generating Bessel beams with on-demand optical parameters and are only focused on creating zeroth-order Bessel beams from optical fibers.