Acoustic amplifying diode using non-reciprocal Willis coupling

Abstract

We propose a concept called acoustic amplifying diode in combining both signal isolation and amplification in a single device. The signal is exponentially amplified in one direction with no reflection and is completely absorbed in another. In this case, the reflection is eliminated from the device in both directions due to impedance matching, preventing backscattering to the signal source. Here, we experimentally demonstrate the amplifying diode using an active metamaterial with non-reciprocal Willis coupling. We also discuss the situation with the presence of both reciprocal and non-reciprocal Willis couplings for more flexibility in implementation. The concept of acoustic amplifying diode will enable applications in sound isolation, sensing and communication, in which non-reciprocity can play an important role.

13 pages, 4 figures

References in corpus (4)

• Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials
• PT-symmetry breaking and laser-absorber modes in optical scattering systems
• Meta-Gratings: Beyond the Limits of Graded Metasurfaces for Wavefront Control
• Active Willis metamaterials for ultra-compact non-reciprocal linear acoustic devices

Cited by in corpus (3)

• Harnessing Nonlinearity to Tame Wave Dynamics in Nonreciprocal Active Systems
• Symmetry-driven Phononic Metamaterials
• Nonreciprocal amplification toward chaos in a chain of Duffing oscillators