Acoustic water display

Cross-boundary communication between media with high impedance mismatch, such as air and water, remains a major challenge for conventional wireless transmission systems. At such interfaces, most of the emitted signal energy is reflected at the media boundaries. Here, we propose a novel display technology for optical information transmission across such an interface, using acoustic radiation pressure to dynamically shape the water-air boundary. The design is based on the combination of spatiotemporal deformations of a water-air interface induced by acoustic radiation pressure. It allows to shape a water-air interface in real-time. By tuning an incident acoustic field at the interface, we demonstrate the ability to generate contactless complex deformation shapes, such as ellipsoidal deformation. Subsequently, we demonstrate the creation of a virtual seven-segment display on the water surface to display numeric values from "0" to "9". This work paves the way for new opportunities to transfer information across the boundary between two media.