Creating compact localized modes for robust sound transport via singular flat band engineering

TL;DR

This paper demonstrates the creation of compact localized sound modes in acoustic Kagome lattices through singular flat band engineering, enabling robust, broadband sound confinement with potential applications in acoustic communication and signal processing.

Contribution

It introduces a novel experimental approach to realize flat-band-induced localized sound modes in acoustic lattices, expanding flat-band physics into acoustics.

Findings

Successful experimental demonstration of compact localized states in acoustic Kagome lattices.

Localized sound confinement achieved over broadband frequencies.

Potential for sound-based information manipulation and transport.

Abstract

We experimentally demonstrate the emergence of flat-band-induced compact-localized modes in acoustic Kagome lattices. Compact localized states populate singular dispersion bands characterized by band crossing, where a quadratic and a flat-band dispersion coalesce into a singularity. These conditions enable intriguing wave phenomena when the Hilbert Schmidt quantum distance, measuring the strength of the singularity, is nonzero. We report numerically and experimentally the formation of compact localized states (CLS), extremely localized in space and protected by dispersion flatness. In our system of coupled acoustic waveguides, sound waves are confined to propagate within tightly localized sites positioned both at the boundaries and within the interior of the lattice, achieving broadband and sustained confinement over time. This framework opens new avenues for the manipulation and transport of information through sound waves, with potential application in mechanics and acoustics, including communication, signal processing, and sound isolation. This work also expands the exploration of flat-band lattice physics within the realm of acoustics.