Exceptional points in cylindrical elastic media with radiation loss

TL;DR

This paper demonstrates the existence of exceptional points in cylindrical elastic media with radiation loss, achieved through optimization of material parameters, which could enhance mechanical sensor performance.

Contribution

It reveals the presence of second- and third-order EPs in multilayered cylindrical elastic systems with radiation loss, a novel finding in elastic wave physics.

Findings

EPs confirmed through numerical experiments

Optimization leads to eigenvalue coalescence

Potential for improved mechanical sensors

Abstract

Exceptional points (EPs) are singular points on a parameter space at which some eigenvalues (scattering poles) and their corresponding eigenmodes coalesce. This study shows the existence of second- and third-order EPs in cylindrical elastic systems with radiation loss. We consider multilayered cylindrical solids under the plane-strain condition placed in a background elastic or acoustic medium. Elastic and acoustic waves propagating in the background media are subject to the radiation loss. We optimize the radii and the material constants of the multilayered solids, such that some scattering poles coalesce on the complex frequency plane. Some numerical experiments are performed to confirm that the coalescence originates from EPs. We expect that this study provides a new approach for enhancing mechanical sensors.