Experimental observations of topologically guided water waves within non-hexagonal structures

TL;DR

This study experimentally demonstrates topologically protected water wave transport in a square lattice, revealing how geometry enables robust wave guiding in dispersive water media, unlike in traditional hexagonal systems.

Contribution

It introduces a novel square lattice design for topological water waves, expanding topological insulator concepts beyond hexagonal structures and dispersive media.

Findings

Topologically protected water wave transport observed in square lattice.

Geometry enables valley-locked wave transport.

Potential applications in energy harvesting and wave filtering.

Abstract

We investigate symmetry-protected topological water waves within a strategically engineered square lattice system. Thus far, symmetry-protected topological modes in hexagonal systems have primarily been studied in electromagnetism and acoustics, i.e. dispersionless media. Herein, we show experimentally how crucial geometrical properties of square structures allow for topological transport that is ordinarily forbidden within conventional hexagonal structures. We perform numerical simulations that take into account the inherent dispersion within water waves and devise a topological insulator that supports symmetry-protected transport along the domain walls. Our measurements, viewed with a high-speed camera under stroboscopic illumination, unambiguously demonstrate the valley-locked transport of water waves within a non-hexagonal structure. Due to the tunability of the energy's directionality by geometry, our results could be used for developing highly-efficient energy harvesters, filters and beam-splitters within dispersive media.