Cloaking and Holography Experiments Using Immersive Boundary Conditions

Wave manipulation for cloaking and holography is difficult in practice, because most techniques are limited in bandwidth and their ability to adapt their response to varying incoming wave fields. In this study, acoustic sources on closed surfaces have their responses calculated and fed back in real time, to suppress forward and backward scattering from objects without prior knowledge of the incident wave field. Furthermore, arbitrary virtual objects can be emulated by changing the boundary conditions applied to the surface. The authors demonstrate these active acoustic boundary conditions in a one-dimensional experiment, to perform broadband cloaking and holography in real time.