Resonance Scattering of an Arbitrary Bessel Beam by a Spherical Object.

Abstract

In our prior work, multipole expansion coefficients of a Bessel beam of arbitrary order with respect to an object of arbitrary location was derived analytically and combined with the T-matrix method to numerically compute the scattering. The present work is extended to directly use the multipole expansion to calculate the scattering from an elastic spherical target. The incident Bessel beam is located at an arbitrary location with respect to the center of the sphere. The far-field resonance scattering in both on- and off-axis incidences is calculated by subtracting an appropriate background from the total scattering based on the resonance scattering theory. The results reveal that the ordinary or helicoidal Bessel beams with selected half-cone angle could lead to resonance suppression at some resonance frequencies for on-axis incidence, however, not for off-axis incidence. The intrinsic property of the elastic scattering contribution from a sphere is shown by the three-dimensional patterns of resonance scattering. The resonance scattering and suppression from thin and thick shells are also noted.