Design and Optimization of an Acoustic Metamaterial Lens

Metamaterials have been of interest in the field of optics for some time as they allow researchers to customize the properties of a material. The same theory that is applied to electromagnetic waves for metamaterial design can also be applied to acoustic waves. Unlike geometric lenses which operate based on their shape, metamaterials can be used to realize flat acoustic lenses without geometric constraints. This property makes metamaterial lenses far more useful for applications where the appearance of the lens is of consequence. For example, a defocusing metamaterial lens for a theatre or concert hall could be constructed out of any aesthetically-pleasing material, be flat, and not lose its functionality. Here, we design an acoustic focusing lens by simulating a geometric lens and its metamaterial equivalent. The equivalency is verified through parameters such as focal length and refractive index.