Realization of ultrathin waveguides by elastic metagratings

Guidance of classical waves is key to many technologies, but high-efficiency, omnidirectional performance is difficult to achieve. Here, an ultrathin, broadband elastic metagrating is proposed for suppression of parasitic diffraction and guiding waves along an arbitrary path. Guiding classical waves has inspired a wealth of nontrivial physics and significant applications. To date, a robust and compact way to guide energy flux traveling along an arbitrary, prescheduled trajectory in a uniform medium is still a fundamental challenge. Here we propose and experimentally realize a generic framework of ultrathin waveguides for omnidirectional wave trapping and efficient routing. The metagrating-based waveguide can totally suppress all high-order parasitic diffractions to route guided elastic waves without leakage. The proposed waveguide protype works in a broad frequency range under a full-angle radiated source. An analytical slab-waveguide model is presented to predict and tailor the diffracted patterns. Compared with existing methods based on topological edge states or defected metamaterials, our meta-waveguide strategy exhibits absolute advantages in compact size, robust performance, and easy fabrication, which may provide a design paradigm for vibration and noise control, energy harvesting, microfluidics, wave steering in acoustics and other waves.

Automated summary

Guiding classical waves is crucial for many technologies, but achieving high-efficiency, omnidirectional performance is challenging. In this study, researchers propose an ultrathin, broadband elastic metagrating for suppressing diffraction and guiding waves along any path. This waveguide exhibits compact size, robust performance, and easy fabrication, making it a promising design paradigm for various wave control applications.