Omnidirectional refractive devices for flexural waves based on graded phononic crystals

TL;DR

This paper introduces omnidirectional refractive devices for flexural waves in thin plates, utilizing graded phononic crystal structures to achieve broadband operation suitable for nano-scale applications.

Contribution

The paper presents a novel design method for omnidirectional refractive devices for flexural waves using graded phononic crystal plates and homogenization theory.

Findings

Devices operate effectively over a broadband frequency range

Luneburg and Maxwell lenses are successfully designed and analyzed

Beam splitters for flexural waves are proposed and validated

Abstract

Different omnidirectional refractive devices for flexural waves in thin plates are proposed and numerically analyzed. Their realization is explained by means phononic crystal plates, where a previously developed homogenization theory is employed for the design of graded index refractive devices. These devices consist of a circular cluster of inclusions with properly designed gradient in their radius. With this approach, the Luneburg and Maxwell lenses and a family of beam splitters for flexural waves are proposed and analyzed. Results show that these devices work properly in a broadband frequency region, being therefore an efficient approach for the design of refractive devices specially interesting for nano-scale applications.