A plasmonic waveguide end-coupled to two plasmonic cavities in a non-Hermitian quantum system for dual-band unidirectional reflectionlessness

Abstract

We demonstrate the possibility of dual-band unidirectional reflectionlessness in a non-Hermitian quantum system composed of a plasmonic waveguide and two end-coupled plasmonic cavities (PCs). Our scheme exhibits dual-band unidirectional reflectionlessness can be obtained at exceptional points by properly adjusting the coupling strength between two PCs, the ratio of decay rates of two PCs, and the ratio of plasmonic cavity-waveguide coupling strengths. As a valuable feature, the quality factor reaches to ∼175.4 in forward direction, while the backward quality factor is close to ∼188.2.

The interference between a giant atom and an internal resonator

“…Some experiments, based on building non-Hermitian Hamiltonians, can also help realize unidirectional reflectionlessness. While they add an internal loss item to the Heisenberg equation of motion [38,39]. , the interference effect leads the photon propagates towards right (blue arrow).…”

Unidirectional Reflectionlessness and Transmissionlessness in Indirectly Coupled Whispering‐Gallery Mode Resonators

“…[35] In 2022, Zhou et al have studied nonreciprocal optical transmission in a spinning resonator system coupled to an atomic ensemble. [40] The aforementioned investigations mainly focused on transmission characteristics, whereas optical devices based on the mechanism of unidirectional reflectionlessness (UR) [41][42][43] can not only protect upper stage optical devices from reflected light in the cascade circuit to improve system stability, but also convey information, similar to transmission. Up to now, UR has demonstrated the significant potential applications in sensors, diodes, isolators, filters, and so on, and thus research on UR continues to grow.…”