Bessel beam

About: Bessel beam is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 42264 citations.

Analysis and design of CP Bessel beam launchers

Abstract: In this paper the focusing capability of a radiating aperture implementing an inward traveling wave current distribution directed along a fixed unit vector is investigated. In particular, it is shown that such a current distribution generates a field profile with its transverse component (with respect to the normal of the radiating aperture) taking the form of a zero-th order Bessel profile. As a practical implementation of the theoretical analysis, a circular-polarized (CP) Bessel beam launcher, made by a radial parallel-plate waveguide loaded with several slot pairs and arranged on a spiral pattern, is designed and optimized. The designed launcher performance agrees with the theoretical model and exhibits an excellent polarization purity.

Near-field Shaping by Leaky-Wave Metasurfaces: OAM and Bessel Beams Synthesis

Abstract: We present and discuss the synthesis of Leaky-wave (LW) radiating metasurfaces for near-field applications. The metasurface sheet transition Impedance Boundary Condition (IBC) is computed after discretizing the relevant Electric Field Integral Equation (EFIE) with Fourier-Bessel basis functions. We have shown that the near-field of the MTS can be controlled with a very good accuracy, down to a height of about one wavelength from the surface. Several examples have been successfully designed, which cover Bessel beam radiators for focusing applications and multiple OAM beams. The designed MTSs are numerically validated with the Method of Moments (MoM).

Focused Bessel beams

Abstract: The diffraction broadening of a focused beam with a Bessel amplitude distribution is examined. Calculations are reported not only of the traditional differential characteristics (radial distributions of the electric-energy densities and of the axial total electromagnetic energy flux in the beam), but also of integral quantities characterising the degree of transverse localisation of the radiation in a tube of specified radius within the beam. It is shown that in a large-aperture Bessel beam only a very small fraction of the total beam power is concentrated in its central core and that a focal point is also observed on intense focusing of the Bessel beam. This spot is not in the geometric-optical focal plane but is displaced from the latter by a certain distance.

Generation of vector Bessel beams with diffractive phase elements based on the Jacobi-Anger expansion.

Abstract: We report the design and optimization of a diffractive phase element whose phase modulation is derived from the Jacobi-Anger relation, which allows the simultaneous generation of multiple scalar Bessel beams of different integer orders. In addition, by the appropriate treatment of a couple of such Bessel beams, we generate a vector Bessel beam of arbitrary order m. This beam is constructed by the collinear superposition of the scalar Bessel beam modes of orders m-1 and m+1, with circular orthogonal polarizations. We demonstrate experimentally both the simultaneous generation of the multiple scalar Bessel beams and the generation of vector Bessel beams of orders m=0 and m=1. These tasks are performed in an optical setup based on a pixelated liquid-crystal spatial light modulator.