Practical realization of a sub-λ/2 acoustic jet.

Autor: Veira Canle D; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland., Kekkonen T; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland., Mäkinen J; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland., Puranen T; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland., Nieminen HJ; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland.; Department of Neuroscience and Biomedical Engineering, School of Science, Aalto University, P.O.B. 12200, FIN-00076, Espoo, Finland., Kuronen A; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland., Franssila S; Department of Chemistry and Materials Science, Aalto University, Espoo, Finland., Kotiaho T; Department of Chemistry, Faculty of Science, P.O.B. 55, FIN-00014, University of Helsinki, Helsinki, Finland.; Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, P.O.B. 56, FIN-00014, University of Helsinki, Helsinki, Finland., Salmi A; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland. ari.salmi@helsinki.fi., Hæggström E; Department of Physics, Division of Materials Physics, Faculty of Science, P.O.B. 64, FIN-00014, University of Helsinki, Helsinki, Finland.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2019 Mar 26; Vol. 9 (1), pp. 5189. Date of Electronic Publication: 2019 Mar 26.
DOI: 10.1038/s41598-019-41335-6
Abstrakt: Studies in optics and acoustics have employed metamaterial lenses to achieve sub-wavelength localization, e.g. a recently introduced concept called 'acoustojet' which in simulations localizes acoustic energy to a spot smaller than λ/2. However previous experimental results on the acoustojet have barely reached λ/2-wide localization. Here we show, by simulations and experiments, that a sub-λ/2 wide localization can be achieved by translating the concept of a photonic jet into the acoustic realm. We performed nano- to macroscale molecular dynamics (MD) and finite element method (FEM) simulations as well as macroscale experiments. We demonstrated that by choosing a suitable size cylindrical lens, and by selecting the speed-of-sound ratio between the lens material(s) and the surrounding medium, an acoustic jet ('acoustic sheet') is formed with a full width at half maximum (FWHM) less than λ/2. The results show, that the acoustojet approach can be experimentally realized with easy-to-manufacture acoustic lenses at the macroscale. MD simulations demonstrate that the concept can be extended to coherent phonons at nanoscale. Finally, our FEM simulations identify some micrometer size structures that could be realized in practice. Our results may contribute to starting a new era of super resolution acoustic imaging: We foresee that jet generating constructs can be readily manufactured, since suitable material combinations can be found from nanoscale to macroscale. Tight focusing of mechanical energy is highly desirable in e.g. electronics, materials science, medicine, biosciences, and energy harvesting.
Databáze: MEDLINE
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