Optical forces from evanescent Bessel beams, multiple reflections, and Kerker conditions in magnetodielectric spheres...

In this work we address, first, the optical force on a magnetodielectric particle on a flat dielectric surface due to an evanescent Bessel beam and, second, the effects on the force of multiple scattering with the substrate. For the first question we find analytical solutions showing that due to the interference of the excited electric and magnetic particle dipoles, the vertical force unusually pushes the object out from the plane. The incident wavelength rules whether or not the illumination constitutes an optical trap. As for the second problem, we make a 2D study with a single evanescent plane wave, and we present the Kerker conditions (so far established for spheres) for magnetodielectric cylinders, showing that in p polarization these conditions are practically reproduced by the latter particles and are associated to minima of the horizontal and vertical forces.