Real- and Fourier-space observation of the anomalous $\pi$-mode in Floquet engineered plasmonic waveguide arrays

TL;DR

This study combines experimental and theoretical approaches to observe and analyze the anomalous Floquet topological π-mode in driven plasmonic waveguide arrays, revealing its unique topological properties and frequency dependence.

Contribution

It provides the first combined real- and Fourier-space experimental observation of the anomalous Floquet topological π-mode in plasmonic waveguides, confirming theoretical predictions.

Findings

Identification of the anomalous Floquet topological π-mode

Demonstration of its frequency dependence

Validation of Floquet theory predictions

Abstract

We present a joint experimental and theoretical study of the driven Su-Schrieffer-Heeger model implemented by arrays of evanescently coupled plasmonic waveguides. Floquet theory predicts that this system hosts for suitable driving frequencies a topologically protected edge state that has no counterpart in static systems, the so-called anomalous Floquet topological $\pi$-mode. By using real- and Fourier-space leakage radiation microscopy in combination with edge- and bulk excitation, we unequivocally identify the anomalous Floquet topological $\pi$-mode and study its frequency dependence.