Breaking the symmetry of momentum conservation using evanescent acoustic fields
Abstract
Although the conservation of momentum is a fundamental law in physics, its constraints are not fulfilled for wave propagation at material boundaries, where incident waves give rise to evanescent field distributions. Whilst non-linear susceptibility tensor terms can provide solutions in the optical regime, this framework cannot be applied directly to acoustic waves. Now by considering a complete representation of wave interactions and scattering at boundaries, we are able to show a generic formalism of sum-frequency mixing for the whole scattering field including all evanescent waves. This general case was studied analytically and verified both numerically and experimentally, showing that considering evanescent waves leads to an anomalous non-linear interaction which enhances sum-frequency generation. This new interpretation not only provides a deeper understanding of the momentum conservation laws in acoustics but also promises translation of this new understanding into optics and photonics, to enhance non-linear interactions.
Citation
Mazilu , M , Demčenko , A , Wilson , R , Reboud , J & Cooper , J 2018 , ' Breaking the symmetry of momentum conservation using evanescent acoustic fields ' , Physical Review Letters , vol. 121 , no. 24 , 244301 . https://doi.org/10.1103/PhysRevLett.121.244301
Publication
Physical Review Letters
Status
Peer reviewed
ISSN
0031-9007Type
Journal article
Rights
© 2018, the Author(s). Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
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