Space-Time Elastic Metamaterials for Zero-Frequency and Zero-Wavenumber Bandgaps

TL;DR

This paper introduces a novel method to create zero-frequency and zero-wavenumber band gaps in wave-matter metamaterials using optical trapping forces, overcoming traditional limitations in elastodynamic systems.

Contribution

The authors demonstrate the use of optomechanical interactions to generate and control zero-frequency and zero-wavenumber band gaps in 3D mass-spring chains, a significant advancement in metamaterial design.

Findings

Zero-frequency band gaps achieved via optical forces.

Zero-wavenumber band gaps created by phase manipulation of masses.

Precise control over bandgap properties demonstrated.

Abstract

We create wave-matter space-time metamaterials using optical trapping forces to manipulate mass-spring chains and create zero-frequency and zero-wavenumber band gaps: the bosonic nature of phonons, and hence this elastodynamic setting, traditionally prohibits either zero-frequency or zero-wavenumber band gaps. Here, we generate zero-frequency gaps using optomechanical interactions within a 3D mass-spring chain by applying an optical trapping force to hold or manipulate a mass in a contactless manner independent of its elastodynamic excitations. Through careful modification of the geometrical parameters in the trapped monoatomic mass-spring chain, we demonstrate the existence of a zero-frequency gap generated by the optical forces on the masses. The precise control we have over the system allows us to drive another set of masses and springs out of phase with its traveling wave thereby creating a zero-wavenumber band gap.