Computation of Bessel Beams in the FDTD Method

Based on the angular spectrum representation (ASR) of the Bessel beams, Bessel beam sources are generated in three-dimensional FDTD using the total-field/scattered-field (TF/ST) method. The correctness and accuracy of the method are verified by comparing the reconstructed field in FDTD with the original field. Comparisons of scattering intensity diagrams calculated using FDTD and those obtained using the generalized Lorenz-Mie theory (GLMT) are implemented for a dielectric sphere illuminated by a Bessel beam, very good agreements have been achieved. The approach presented in this paper can be applied to generate other structured beam sources in FDTD, which provides an access to solve structured beam scattering by complex particles using FDTD.