Reconfigurable Enhancement of Actuation Forces by Engineered Losses in non-Hermitian Metamaterials

TL;DR

This paper demonstrates how engineered losses in non-Hermitian metamaterials with exceptional point degeneracies can reconfigure actuation forces and enhance emission without degrading signal quality, opening new avenues for advanced actuators and emitters.

Contribution

It introduces a novel approach using non-Hermitian metamaterials with EPDs to enhance actuation forces and emission properties while maintaining signal integrity.

Findings

Enhanced actuation force via EPD in elastodynamics

Maintained signal quality despite force enhancement

Boosted Purcell emissivity beyond expected levels

Abstract

While boosting signals with amplification mechanisms is a well established approach, attenuation mechanisms are typically considered an anathema because they degrade the efficiency of the structures employed to perform useful operations on these signals. An emerging alternate viewpoint promotes losses as a novel design element by utilizing the notion of exceptional point degeneracies (EPDs) points in parameter space where the eigenvalues of the underlying system and the associated eigenvectors simultaneously coalesce. Here, we demonstrate a direct consequence of such eigenbasis collapse in elastodynamics, an unusual enhancement of actuation force by a judiciously designed non-Hermitian metamaterial supporting an EPD that is coupled to an actuation source. Intriguingly, the EPD enables this enhancement while maintaining a constant signal quality. Our work constitutes a proof-of-principle design which can promote a new class of reconfigurable nano-indenters and robotic-actuators. Importantly, it reveals the ramifications of non-Hermiticity in boosting the Purcell emissivity enhancement factor beyond its expected value, which can guide the design of metamaterials with enhanced emission that does not deteriorate signal quality for mechanical, acoustic, optical, and photonic applications.