Novel transmission property of zero-index metamaterial waveguide doped with gain and lossy defects

Abstract

Taking inspiration from quantum parity–time (PT) symmetries that have gained immense popularity in the emerging fields of non- Hermitian optics and photonics, the interest of exploring more generalized gain-loss interactions is never seen down. In this paper we theoretically present new fantastic properties through a zero-index metamaterial (ZIM) waveguide loaded gain and loss defects. For the case of epsilon-and-mu-near-zero (EMNZ) based ZIM medium, electromagnetic (EM) waves are cumulative and the system behaves as an amplifier when the loss cavity coefficient is greater than the gain cavity coefficient. Conversely, when loss is less than gain, EM waves are dissipated and the system behaves as an attenuator. Moreover, our investigation is extended to non-Hermitian scenarios characterized by tailored distributions of gain and loss in the epsilon-near-zero (ENZ) host medium. The transport effect in ZIM waveguide is amplified in one mode, while it is dissipative in the other mode, which breaks the common sense and its physic is analyzed by magnetic flux. That is which cavity has the smaller loss/gain coefficient, the larger its magnetic flux, which cavity dominates. This paper is of significant importance in the manipulation of electromagnetic waves and light amplification as well as the enhancement of matter interactions.