Switchable omnidirectional acoustic insulation through open window structures with ultrathin metasurfaces

Abstract

We theoretically propose and experimentally realize two types of open window structures that exhibit an unusual functionality of switchable omnidirectional acoustic insulation in two different ways. Both types of open window structures consist of an array of blades that are attached with ultrathin metasurfaces on both sides. Based on the acoustic manipulation ability of the metasurfaces, omnidirectional acoustic insulation can be realized in the open windows. Interestingly, such an effect is switchable by simply changing the configuration of the blade array. For the first type, omnidirectional acoustic insulation can be switched on or off by adjusting the distance between two adjacent blades. For the second type in which the open window structure is composed of an alternative arrangement of two types of blades, acoustic insulation can be controlled by moving one kind of blade horizontally. The proposed open windows have the advantage of broadband omnidirectional acoustic insulation and convenient switching mechanisms. Our work opens up a new approach for acoustic insulation in open structures, with potential applications in a variety of fields, such as noise control and architectural acoustics.