Bidirectional elastic diode with frequency-preserved nonreciprocity

TL;DR

This paper introduces a bidirectional elastic diode that achieves nonreciprocal wave propagation with frequency preservation, high quality, and amplitude modulation, enabling advanced control of elastic wave transport in metamaterials.

Contribution

It presents a novel elastic diode design with three mechanisms to break reciprocity, combining nonlinear resonance, interface reflection, and damping effects, both theoretically and experimentally.

Findings

Demonstrated bidirectional nonreciprocal elastic wave rectification

Achieved frequency-preserving wave insulation with high quality

Enabled amplitude-controlled modulation of wave propagation

Abstract

The study of nonreciprocal wave propagation is of great interests for both fundamental research and engineering applications. Here we demonstrate theoretically and experimentally a bidirectional, nonreciprocal, and high-quality diode that can rectify elastic waves in both forward and backward directions in an elastic metamaterial designed to exhibit enhanced nonlinearity of resonances. This diode can preserve or vary frequency, rectify low-frequency long wave with small system size, offer high-quality insulation, can be modulated by amplitude, and break reciprocity of both the total energy and fundamental wave. We report three mechanisms to break reciprocity: the amplitude-dependent bandgap combining interface reflection, chaotic response combining linear bandgap, amplitude-dependent attenuation rate in damping diode. The bidirectional diode paves ways for mutually controlling information/energy transport between two sources, which can be used as new wave insulators.