Epistemology

Scattering

Programming language

Metamaterial

Philosophy

Telecommunications

Physics

Degrees of freedom (physics and chemistry)

Ideal (ethics)

Optics

Acoustics

Plane wave

Quantum mechanics

Reflection (computer programming)

Refraction

Computer science

Wavefront

Transmission (telecommunications)

Nature Communications

Recent advances in gradient metasurfaces have shown that only by locally controlling the bianisotropic response of the constituent cells can one ensure full control of refraction, i.e., arbitrarily modify the direction of the incident waves without producing scattering into unwanted directions. In this work, we propose and experimentally verify the use of a new acoustic cell architecture that provides enough degrees of freedom to fully control the bianisotropic response and minimizes the implementation losses produced by resonant elements. The versatility of the approach is shown through the design of three different anomalous refractive metasurfaces capable of redirecting a normally incident plane wave to 60, 70 and 80 degrees on transmission. The effciency of the bianisotropic designs is over 90%, much higher than the corresponding designs based on the conventional generalized Snells law (81%, 58%, and 35%). The proposed strategy opens a new way of designing practical and highly effcient bianisotropic metasurfaces for different functionalities, enabling nearly ideal control over the acoustic energy flow through thin metasurfaces.

Systematic design and experimental demonstration of bianisotropic metasurfaces for scattering-free manipulation of acoustic wavefronts