Negative Reflection and Refraction of Guided Elastic Waves– Metamaterials 2018

We report on the experimental implementation of negative refraction phenomena with guided elastic waves. On the one hand, we explore the analogy between negative reflection and phase conjugation for the control of waves in random scattering and chaotic media. On the other hand, we implement the concept of complementary media and the ability to cancel the propagation of waves by adjoining two mirror regions of opposite refractive indices. To that aim, a semi-analytical model and FDTD numerical simulations have been developed to optimize and design these acoustic devices. Wave propagation through the designed elastic plates is experimentally investigated by means of laser interferometry.