Phys.org  July 28, 2022 Aided by a reflecting surface, the acoustic carpet cloak has become one of the most practically feasible invisibility devices. However, due to the difficulty in the realization of ideal material parameters, the underwater carpet cloaks could only work for a small incident angle. Researchers in China designed an underwater carpet cloak using a three-component metafluid composed of syntactic foam, steel, and water. The syntactic foam, which is synthesized from epoxy resin and hollow glass microspheres, exhibits lower mass density and higher sound velocity relative to water. By periodically embedding the syntactic foam and steel rods in […]