Confined acoustic line modes within a glide-symmetric waveguide (article)

This is the final version. Available from Nature Research via the DOI in this record. The dataset associated with this article is available in ORE at: https://doi.org/10.24378/exe.3903Confined coupled acoustic line-modes supported by two parallel lines of periodic holes on opposite surfaces of a glide-symmetric waveguide have a hybrid character combining symmetric and anti-symmetric properties. These hybrid coupled acoustic line-modes have a near constant group velocity over a broad frequency range as no band gap is formed at the first Brillouin zone boundary. We show that the hybrid character of these confined modes is tuneable as a function of the spacing between the two surfaces. Further we explore how the band-gap reappears as the glide symmetry is broken.Engineering and Physical Sciences Research Council (EPSRC)Defence Science and Technology Laboratory (DSTL)Defence Science and Technology Laboratory (DSTL