Tailored elastic surface to body wave Umklapp conversion

Gregory J. Chaplain; Jacopo M. De Ponti; Andrea Colombi; Rafael Fuentes-Dominguez; Paul Dryburg; Don Pieris; Richard J. Smith; Adam Clare; Matt Clark; Richard V. Craster

doi:10.1038/s41467-020-17021-x

arXiv · 1912.05373

Tailored elastic surface to body wave Umklapp conversion

Gregory J. Chaplain·Jacopo M. De Ponti·Andrea Colombi·Rafael Fuentes-Dominguez·Paul Dryburg·Don Pieris·Richard J. Smith·Adam Clare·Matt Clark·Richard V. Craster

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Abstract

Elastic waves guided along surfaces dominate applications in geophysics, ultrasonic inspection, mechanical vibration, and surface acoustic wave devices; precise manipulation of surface Rayleigh waves and their coupling with polarized body waves presents a challenge that offers to unlock the flexibility in wave transport required for efficient energy harvesting and vibration mitigation devices. We design elastic metasurfaces, consisting of a graded array of rod resonators attached to an elastic substrate that, together with critical insight from Umklapp scattering in phonon-electron systems, allow us to leverage the transfer of crystal momentum; we mode-convert Rayleigh surface waves into bulk waves that form tunable beams. Experiments, theory and simulation verify that these tailored Umklapp mechanisms play a key role in coupling surface Rayleigh waves to reversed bulk shear and compressional waves independently, thereby creating passive self-phased arrays allowing for tunable redirection and wave focusing within the bulk medium.

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Gregory J. Chaplain, Jacopo M. De Ponti, Andrea Colombi, Rafael Fuentes-Dominguez, Paul Dryburg, Don Pieris, Richard J. Smith, Adam Clare, Matt Clark, Richard V. Craster. 2019-12-11. Tailored elastic surface to body wave Umklapp conversion. https://doi.org/10.1038/s41467-020-17021-x

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