Sub- and supersonic elastic waves in an annular hole phononic metamaterial

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The raw modelling data from Fig. 1 (Supplementary Data 1–4) and to produce Fig. 2 (Supplementary Data 5–7) is provided in the supplementary information accompanying this paper and data analysis methods used to produce Fig. 2 are described throughout this paper. The data used to calculate the simulated Array #2 transmission data shown in Supplementary Fig. 7 is provided in Supplementary data 8 accompanying this paper. The data used to calculate the simulated phase velocity for Array #2 at 97 MHz is provided in Supplementary data 9–10 accompanying this paper. Original LDV videos from which Fig. 6 was extracted are also provided as Supplementary Videos 4 and 5 accompanying this paper.Surface acoustic wave (SAW) devices are used in a wide range of applications including sensing and microfluidics, and are now being developed for applications such as quantum computing. As with photonics, and other electromagnetic radiation, metamaterials offer an exciting route to control and manipulate SAW propagation, which could lead to new device concepts and paradigms. In this work we demonstrate that a phononic metamaterial comprising an array of annular hole resonators can be used to realise frequency control of SAW velocity. We show, using simulations and experiment, that metamaterial patterning on a lithium niobate substrate allows control of SAW phase velocities to values slower and faster than the velocity in an unpatterned substrate; namely, to ~85% and ~130% of the unpatterned SAW velocity, respectively. This approach could lead to novel designs for SAW devices, such as delay lines and chirp filters, but could also be applied to other elastic waves.Leverhulme Trus