Manipulation of circular polarization and mechanical waves in gyroscopic metamaterials

Gyroscopic metamaterials integrate rotational units within periodic structures, enabling precise manipulation of mechanical waves and exhibiting programmable material properties. This study delves into the polarization characteristics of one-dimensional (1D) chains and two-dimensional (2D) networks of gyroscopic metamaterials, highlighting the ability to modulate the dispersion band structure through rotational elements. By leveraging dynamic tunability, we effectively tune the band gaps for polarized waves across a broad frequency range. Through wave polarization, we discover a Faraday-like rotation effect in linearly polarized mechanical waves. By adjusting the input frequency or the spin speed, the manipulation of the polarization plane and the polarization state can be achieved, effectively replicating the phenomena of an optical model in a mechanical system. We confirm that 2D rectangular and triangular unit-cell gyroscopic metamaterials can serve as tunable filtering and tunable polarizing components, respectively. Additionally, we utilize circularly polarized waves to achieve selective excitation, enabling waves at the same frequency to exhibit diverse propagation patterns. Experimental validation in 1D systems confirms the capability of manipulating wave propagation through the generated polarization. Our research establishes a framework for exploring gyroscopic metamaterials' capabilities in wave manipulation, fostering innovation in signal processing technologies.