A Solution of Scattered Field of Particle in Electromagnetic Beam Based on Beam Series Expansion

Based on the orthogonalities among the spherical vector wave functions, the expressions of scattering fields are developed as the particle being irradiated by the zeroth-order field and the first-order fields of x, y, and z. A general relation between the expansion coefficients of scattering field and incident field is presented. With the example of the elliptical beam, the scattering property of a particle in beam is investigated. Upon analyzing of the effects of the beam waist, irradiating distance, etc., on scattering property, the validity of the algorithm used is demonstrated. The results show that the beam waist may improve the particle´s identification property and the particle has a strong scattering property in both forward and backward directions. The method used is simple and provides a new way for investigating the scattering fields from particles in electromagnetic beams.