Degrees of circular polarization for the electromagnetic waves induced by electric point dipoles

Abstract

An electric point dipole is the simplest model for emitters, antennas, and other nanostructures. For a dipole sufficiently small in comparison to the wavelength of the radiated electromagnetic wave, its electric-field intensity and Poynting vector are fully understood. Firstly, both decrease in magnitude with increasing radial distance from the dipole location. Secondly, the Poynting vector increases in magnitude with the sinusoid squared of the polar angle measured from the dipolar axis. We will consider here the degree of circular polarization (CP) of the electromagnetic wave induced by an electric point dipole. Resultantly, we learned that the near-perfect CP states form a pair of hollow-cylindrical surfaces. The radius of those surfaces designating near-perfect CP states is approximately one wavelength detached from the dipolar axis. However, these pictures are appreciably altered for the electromagnetic field induced by an array of electric point linear dipoles.