Light scattering of a non-diffracting zero-order Bessel beam by uniaxial anisotropic bispheres

Based on the generalized multi-particle Mie theory and the Fourier transformation approach, light scattering of two interacting homogeneous uniaxial anisotropic spheres with parallel primary optical axes illuminated by a zero-order Bessel beam (ZOBB) is investigated. The size and configuration of the particles are arbitrary. The expansion expressions of the ZOBB are given in terms of the spherical vector wave functions (SVWFs) and the expansion coefficients are derived. Utilizing the vector addition theorem of the SVWFs, the interactive scattering coefficients are derived through the continuous boundary conditions on which the interaction of the bispheres is considered. The effects of the conical angle, beam centre position, sphere separation distance, and anisotropic parameters on the far-region field distributions are numerically analyzed in detail. Some results are compared with those results for a Gaussian beam incidence. Selected results of bispheres consisting of typical medium such as TiO₂, SiO₂, Silicon, water are exhibited. This investigation could provide an effective test for further research on the scattering characteristic of an aggregate of anisotropic spheres by a high-order Bessel vortex beam and radiation forces, which are important in optical tweezers and particle manipulation applications. - Highlights: • Scattering of a zero-order Bessel beam by uniaxial anisotropic bispheres is studied. • The parallel primary optical axes of the anisotropic spheres are considered. • The accuracy of the theory and codes is verified. • Scattering performances of uniaxial anisotropic bispheres are numerically discussed. • Different properties of multiple scattering by a zero-order Bessel beam are shown