Force on an electric dipole near an ENZ Interface

An electric dipole near a surface is subject to the electromagnetic force by its own reflected field. We have derived a closed-form expression for this force for the case of an epsilon-near-zero (ENZ) medium. This force is perpendicular to the surface, and it is repulsive. We show that this force is due to the evanescent reflected field. For a rotating dipole moment, there is also a lateral force, which, in the ENZ limit, is vanishing small. However, when a small amount of damping is present in the material, this force becomes comparable with the force component perpendicular to the surface. (C) 2019 Optical Society of America