Shaping High-Order Diffraction-Free Beams Through Continuous Superposition of Bessel Beams

Abstract

Recognized for their non-diffracting properties, Bessel beams can be conveniently combined to generate the so-called Frozen Waves, which are monochromatic beams endowed with topological charge and whose longitudinal intensity pattern can be shaped according to a previously chosen function. Continuous superposition of Bessel beams is specially suitable for micrometer-scale domains, being highly relevant for applications in optical tweezers, particle trapping and atom guidance. Previous studies have successfully constructed micrometer Frozen Wave solutions with null topological charge; nevertheless, some challenges persist in obtaining exact solutions when dealing with higher topological charge values (i.e., higher-order micrometer Frozen Waves). Typically, a topological charge raising operator is used to elevate the order; however, such solutions face significant issues when the orders become excessively high. In this paper, based in continuous superposition of higher order Bessel beams, we develop a novel analytic and exact solution for higher-order micrometer Frozen Waves, so obtaining a method for modeling the intensity of beams with arbitrary topological charge within micrometer spatial domains. We also investigate the behavior of the electric field's longitudinal component in such highly non-paraxial regimes through a vectorial treatment.