Polarization state conversion achieved by chiral mechanical metamaterial

• Published in: New journal of physics Vol. 26; no. 2; pp. 23053 - 23065
• Main Authors: Mangach, Hicham, Achaoui, Younes, Kadic, Muamer, Bouzid, Abdenbi, Guenneau, Sébastien, Zeng, Shuwen
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.02.2024; Institute of Physics: Open Access Journals
• Subjects: Acoustic properties; Atomic properties; chiral metamaterial; Condensed Matter; Connectors; Mass-spring systems; Materials Science; Mathematical Physics; Metamaterials; micro-rotation; monatomic mass-in-mass unit cell; Optics; Physics; Polarization; polarization control; Propagation; Shear; Structural design; Wave propagation; micro-rotation; polarization control; monatomic mass-in-mass unit cell; chiral metamaterial
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/ad2745

Recently, metamaterials have driven advancements in wave propagation and polarization control. Chiral elastic metamaterials, in particular, have attracted considerable attention due to their distinctive properties, such as acoustical activity and auxeticity. Such characteristics arise from the additional degrees of freedom for tuning the embedded micro- and macro-rotations. In this study, we demonstrate an unusual energy exchange between longitudinal and in-plane shear waves in a 3D chiral mechanical metamaterial. The structural design is capable of inducing up to a 90 ∘ rotation in the plane of polarization. Additionally, this capacity for conversion is achieved by employing both an arrangement of chiral cells and a single meta-atom. This peculiar behavior enables a seamless switch between the three polarization states existing within a solid material, namely, the longitudinal state, the shear horizontal state, and the shear vertical state. Furthermore, a 2D discrete mono-atomic mass-spring model featuring inclined connectors is used to characterize the distinctive energy exchange between modes. This characterization is based on the retrieval of the pertinent elastic coefficients. The engineered chiral metamaterial polarization converter stands as a promising device for momentum conservation conversions and applications in elasto-dynamic polarimetry.