Switchable Unidirectional Radiation from Huygens Dipole Formed at an Exceptional Point in Non-Hermitian Plasmonic Systems

Abstract

Non-Hermitian (NH) photonics has attracted considerable attention from researchers owing to exotic properties that originate from the parity-time (Formula Presented) phase transition and exceptional points (EPs). In this work, we propose and numerically demonstrate formation of a Huygens dipole using an EP eigenstate in NH coupled plasmonic systems. Unidirectional radiation from the artificial Huygens dipole can be switched via the sign of a coupling constant. In our systems, the formation of the Huygens dipole and its switchable unidirectional radiation are manifested as long as the EP condition is fulfilled. The presented method to control artificial electric and magnetic dipoles based on NH systems would provide new roots to construct Huygens metasurfaces and Huygens dipole antennas.