Non-Hermitian interferometer: Unidirectional amplification without distortion

TL;DR

This paper introduces a non-Hermitian interferometer design that achieves unidirectional wave amplification and absorption without distortion, leveraging spectral singularities for potential applications in wave control.

Contribution

It proposes a novel non-Hermitian dimer with unequal hopping rates that enables wave amplification and absorption without distortion, independent of wave vector.

Findings

Wavepacket amplification without distortion

Absorption of incoherent waves without reflection

Spectral singularities govern absorption behavior

Abstract

A non-Hermitian interferometer can realize asymmetric transmission in the presence of imaginary potential and magnetic flux. Here, we propose a non-Hermitian dimer with an unequal hopping rate by an interferometer-like cluster in the framework of tight-binding model. The intriguing features of this design are the wave-vector independence and unidirectionality of scattering, which amplifies wavepacket without distortion and absorbs incoherent wave without reflection. The absorption relates to the system spectral singularities, the dynamical behaviors of the spectral singularities are also investigated analytically and numerically.