Radiation forces on a Mie particle in the evanescent field of an optical waveguide

We use a generalization of Mie theory - the so-called Arbitrary Beam Theory - to calculate the scattered field and radiation forces on a dielectric spherical particle in the evanescent field of an optical waveguide with a step index profile. The guiding velocities calculated by us agree well with experimental results reported by other groups. Moreover, the occurrence of resonances in the scattered field has the consequence that the particle is repelled from, instead of being attracted to, the waveguide for certain values of particle refractive index and radius.