Controlling The Direction And Intensity Of Magnetic Dipole Emission By Spoof Plasmonic Structures

In this paper, we demonstrate that the direction and intensity of the magnetic dipole emission can be manipulated simultaneously by using spoof plasmonic structures. First, by placing two spoof plasmonic structures around a bare magnetic dipole source, we investigate the influence of the orientation of the spoof plasmonic structures on the direction of magnetic dipolar emission. We find that the direction of bare magnetic dipole emission can be freely tuned from 0 degrees to 360 degrees by rotating the two spoof plasmonic structures due to the stimulation of structured magnetic dipolar mode. Furthermore, an array antenna composed of three plasmonic structures is designed; we discuss the manipulation of the intensity and the direction of magnetic dipole emission by three spoof plasmonic structures. The theoretical results show that the intensity of magnetic dipole emission can be effectively enhanced and the direction can be freely selected. In addition, we also investigate the influence of structural variation of the cylinder structure on the intensity and enhancement factor. Our calculated results indicate that the enhancement factor of magnetic dipole emission can reach more than 580 with tuning structural parameters at the resonant frequency of the magnetic dipolar mode. Finally, we discuss the effect of real materials on the external quantum efficiency, and the quantum efficiency is still very high in our design. As such, these results underscore the unique ability of manipulating the intensity and the direction of magnetic dipole emission, opening new technological avenues in the magneto-optical domain. Published under license by AIP Publishing.