Perfect Generation of Angular Momentum with Cylindrical Bianisotropic Metasurfaces

TL;DR

This paper introduces a novel bianisotropic cylindrical metasurface design that achieves perfect transformation of cylindrical waves, including their angular momentum, demonstrated experimentally in acoustics.

Contribution

It develops a new design methodology for bianisotropic cylindrical metasurfaces enabling perfect wavefront and angular momentum transformation, a previously unexplored area.

Findings

First experimental demonstration of perfect angular momentum transformation in acoustics.

Development of a formalism for designing bianisotropic cylindrical metasurfaces.

Achieved maximum efficiency in wavefront control for cylindrical waves.

Abstract

Recent advances in metasurfaces have shown the importance of controlling the bianisotropic response of the constituent meta-atoms for maximum efficiency wavefront transformation. Under the paradigm of a bianisotropic metasurface, full control of the local scattering properties is allowed opening new design avenues for creating reciprocal metasurfaces. Despite recent advances in the perfect transformation of both electromagnetic and acoustic plane waves, the importance of bianisotropic metasurfaces for transforming cylindrical waves is still unexplored. Motivated by the possibility of arbitrarily controlling the angular momentum of cylindrical waves, we develop a design methodology for a bianisotropic cylindrical metasurface that enables perfect transformation of cylindrical waves. This formalism is applied to the acoustic scenario and the first experimental demonstration of perfect angular momentum transformation is shown.