Light scattering of Laguerre–Gaussian beams: near-field structures and symmetries

We apply the method of far-field matching to remodel laser beams and study light scattering from spherical particles illuminated by a Laguerre–Gaussian (LG) light beam. The optical field in the near-field region is analyzed for purely azimuthal LG beams characterized by a nonzero azimuthal mode number $m_{\mathrm{LG}}$. The morphology of photonic nanojets is shown to significantly vary, depending the mode number and the scatterer’s characteristics. The cases of negative index metamaterial and metallic Mie scatterers are discussed. We also discuss the symmetry properties of laser beams and related results for the optical forces. The near-field structure of optical vortices associated with the components of the electric field, being highly sensitive to the mode number, is found to be determined by the twofold rotational symmetry.