Non-Hermitian topological coupler for elastic waves

Non-Hermitian topological systems, by combining the advantages of topological robustness and sensitivity induced by non-Hermiticity, have recently emerged and attracted much research interest. Here, we propose a device based on the topological coupler in elastic waves with non-Hermiticity, which contains two topological domain walls and four ports. In this device, topological robustness routes the transmission of waves, while non-Hermiticity controls the gain or loss of waves as they propagate. These mechanisms result in continuous and quantitative control of the energy distribution ratio of each port. A non-Hermitian Hamiltonian is introduced to reveal the coupling mechanism of the topological coupler, and a scattering matrix is proposed to predict the energy distribution ratio of each port. The proposed topological coupler, which provides a new paradigm for the non-Hermitian topological systems, can be employed as a sensitive beam splitter or a coupler switch. Moreover, the topological coupler has potential applications in information processing and logic operation in elastic circuits or networks, and the paradigm also applies to other classical systems.

Automated summary

This article introduces a new device based on non-Hermitian topological systems, which combines the advantages of topological robustness and non-Hermiticity to achieve continuous and quantitative control of energy distribution ratio of waves. The device can be used as a sensitive beam splitter or a coupler switch, with potential applications in elastic circuits or networks.