Surface corrugated laminates as elastic grating couplers: splitting of SV- and P-waves by selective diffraction

TL;DR

This paper introduces surface corrugated laminates that act as elastic grating couplers, enabling selective diffraction and splitting of P- and SV-waves in elastic systems, with potential applications in wave control.

Contribution

It presents a novel design of elastic grating couplers that achieve frequency, angle, and wave-type selective diffraction for elastic waves, including wave splitting and negative refraction.

Findings

Successful design of elastic grating couplers with wave-type selectivity

Demonstration of splitting and redirecting P- and SV-waves

Use of transfer matrix method to analyze isofrequency contours

Abstract

The phenomenon of selective diffraction is extended to in-plane elastic waves and we design surface corrugated periodic laminates that incorporate crystal momentum transfer which, due to the rich physics embedded within the vector elastic system, results in frequency, angle and wave-type selective diffraction. The resulting devices are elastic grating couplers, with additional capabilities as compared to analogous scalar electromagnetic couplers, in that the elastic couplers possess the ability to split and independently redirect, through selective negative refraction, the two body waves present in the vector elastic system: compressional (P) and shear-vertical (SV) elastic waves. The design paradigm, and interpretation, is aided by obtaining isofrequency contours via a non-dimensionalised transfer matrix method.