Topological ventilated sound switch from acoustic Su-Schrieffer–Heeger model

In the last two decades, the emergence of acoustic metamaterials has offered previously unimaginable possibilities for extraordinary control of sound waves. For example, various extremely light-weight sound attenuation systems based on metamaterials and phononic crystals have been demonstrated. Equipped with reconfigurability, such systems will provide the on-demand controls of the passage or stopping of sound waves and are often called acoustic switches or sound switches. However, so far, no ventilated sound switch has been proposed, which can realize both satisfying sound transmission and ventilation. In this work, we demonstrate a topological ventilated sound switch achieving switchable transmission. This switch is based on the one-dimensional acoustic Su-Schrieffer–Heeger model, which leads to the appearance of the topological interface states, and the sound can be turned on or off with the desired ventilation performance. With only one topological unit, the high transmission ratio (∼20 dB) before and after switch has been demonstrated in both simulations and experiments. It should have potential applications in areas of the acoustic engineering where both specific frequency sound transmission and ventilation are required.