Fig. 4: Corner mode measurement.
From: Acoustic higher-order topological insulator from momentum-space nonsymmorphic symmetries
a Setup for measuring the spectral response. The inset is a zoom-in for better showing the source-detector positioning of the sound source and the probing microphone. Simulated (b) and measured (c) spectra of bulk (yellow), edge (brown), and corner (green) modes. Measured (d–f) and simulated (g–i) pressure intensity distributions for bulk, edge, and corner modes with frequencies being 8042 Hz, 9006 Hz, and 8595 Hz, respectively.
