Photophoretic asymmetry factors for an absorptive dielectric cylinder near a reflecting planar boundary

Abstract

The effect of a perfectly reflecting boundary (i.e., planar wall) on the photophoretic asymmetry factors (PAFs) for an absorptive dielectric cylinder is investigated. The expression for the normalized intensity function for the electric field internal to the cylinder is used in conjunction with the multiple scattering theory of waves, the translational addition theorem in cylindrical coordinates, and the method of images to derive analytically and compute numerically the longitudinal (L) and transverse (T) PAFs for the cylinder as well as the internal dimensionless intensity function. Both TM- and TE-polarized plane progressive waves with arbitrary incidence (in the polar plane) are considered. Particular emphases are given on the dimensionless size parameter of the cylinder, the incidence angle of the illuminating field, and the dimensionless distance parameter from the flat surface. The results show that the net effect of the planar wall increases or decreases the amplitudes of the PAFs (thus, the photophoretic force and torque), depending on the particle-wall distance, incidence angle, particle size, and the polarization of the incident field. The results of this analysis are useful in applications related to electromagnetic/optical scattering, particle manipulations, optically bound matter, and photophoresis.