THEORETICAL AND EXPERIMENTAL INVESTIGATION OF ELASTIC WAVES PROPAGATION IN CURVED SPACE

摘要

One fascinating possibility allowed in general relativity is a wormhole which can link distant locations or even separate universes however without supporting evidence. The recent transformation optics (TO) provide a powerful tool to mimic cosmic phenomena like the optical black hole, cosmic string, and even the wormhole. However, an experimental realization of such a wormhole seems impossible and remains a challenge due to the necessity of extreme material profile. By incorporating the intrinsic curvature of deformed plates for the case of flexural wave propagation, the stringent material requirement can be relaxed and we demonstrate a two-dimensional analog of wormhole using merely homogeneous materials within a curved laboratory frame. The experimental observation of the wave propagation, tunneling behavior, imaging and caustic effects in the wormhole are in excellent agreement with the theoretical analysis. Our geometric curvature approach shows the great potential of developing curvature-driven device such as wavefront shaping, acoustic surface wave sensing, and curved surface waveguiding.