Breaking the Symmetry of Momentum Conservation Using Evanescent Acoustic Fields.
Phys Rev Lett
; 121(24): 244301, 2018 Dec 14.
Article
em En
| MEDLINE
| ID: mdl-30608756
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. While nonlinear 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 for ultrasonic waves, showing that considering evanescent waves leads to an anomalous nonlinear 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 nonlinear interactions.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Reino Unido