Elastic Temporal Waveguiding

TL;DR

This paper introduces a theoretical framework for elastic waveguiding using slow time-modulation of lattice stiffness, enabling frequency conversion and wave steering without back-scattering, with potential applications in elastic wave information transport.

Contribution

It develops a novel approach to control elastic wave propagation through time-modulated lattices, eliminating reflections and enabling wave steering in 1D and 2D systems.

Findings

Frequency conversion achieved without back-scattering.

Wave steering demonstrated in 2D lattices.

Reflections minimized by slow modulation based on adiabatic theorem.

Abstract

We provide a theoretical framework to mold time-modulated lattices with frequency conversion and wave-steering capabilities. We initially focus on 1D lattices, whereby a sufficiently slow time-modulation of the stiffness is employed to convert the frequency content of impinging waves. Based on the adiabatic theorem, we demonstrate that undesired reflections, which emerge in time-discontinuous materials, can be eliminated by a careful choice of the modulation velocity. The concept is later explored in the context of 2D lattices, whereby a slow time modulation of the stiffness not only induces frequency conversion without back-scattering, but also serves as a mechanism to steer waves. Our paper explores a new and exciting way to control wave propagation in elastodynamics with scattering-free guiding capabilities, and may open new avenues for the manipulation and transport of information through elastic waves.