Beam Shape Coefficients of Hollow Vortex Gaussian Beam and Near-Field Scattering

The beam shape coefficients (BSCs) of the electromagnetic field of hollow vortex Gaussian beams (HVGBs) are formulated, based on the spherical wave expansion of the scalar function. The cylindrical wave spectrum decomposition is employed to expand the scalar function in the spherical coordinates. Numerical results on the beam field reproduced from the BSCs confirm that the BSC evaluation is efficient and reliable. The scattering in the near-field zone is calculated and discussed, revealing the dependence of the straight and curved photonic jets on the topological charge of the HVGB. The paper may be useful for studying the interaction between the HVGB anda spherical particle. (c) 2024 Optica Publishing Group