Realization of ultrathin waveguides by elastic metagratings

Abstract

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.

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.