Dynamics of a small dielectric sphere due to the higher-order modes of an optical nano fiber

We investigate the dynamics of a submicron-scale, dielectric sphere in the electromagnetic field from an optical nanofiber. Modeling the sphere as a damped, oscillating dipole driven by the nanofiber field, we calculate the time-averaged force on the sphere. For a given monochromatic field, we quantify the dependence of this force on the radii of the sphere and the nanofiber, as well as the the refractive indices of the sphere, nanofiber, and surrounding region. We analyze the resulting motion of the sphere in the presence of several higher-order nanofiber modes.