Scattering-coded elastic meta-boundary.

Object localization through active elastic waves is a crucial technology, but generally requires a transducer array with complex hardware. Although computational sensing has been demonstrated to be able to overcome the short-comings of transducer array by merging artificially designed structures into sensing process, coding spatial elastic waves for active object identification is still a knowledge gap. Here we propose a scattering-coded elastic meta-boundary composed of randomly distributed scatterers for computational identification of objects with a single transducer. The multiple scattering effect of the meta-boundary introduces complexity into scattered fields to achieve a highly uncorrelated scattering coding of elastic waves, thereby eliminating the ambiguity of the object location information. We demonstrate that the locations of objects can be uniquely identified by using the scattering coding of our designed meta-boundary, delivering a design of meta-boundary touchscreen for human-machine interaction. The proposed scattering-coded meta-boundary opens up avenues for artificially designed boundaries with the capability of information coding and identification, and may provide important applications in wave sensing, such as structural monitoring, underwater detection, indoor localization, and biomedical imaging.