Acoustic metamaterial for subwavelength edge detection
Metamaterials have demonstrated the possibility to produce super-resolved images by restoring propagative and evanescent waves. However, for efficient information transfer, for example, in compressed sensing, it is often desirable to visualize only the fast spatial variations of the wave field (carried by evanescent waves), as the one created by edges or small details. Image processing edge detection algorithms perform such operation, but they add time and complexity to the imaging process. Here we present an acoustic metamaterial that transmits only components of the acoustic field that are approximately equal to or smaller than the operating wavelength. The metamaterial converts evanescent waves into propagative waves exciting trapped resonances, and it uses periodicity to attenuate the propagative components. This approach achieves resolutions ~5 times smaller than the operating wavelength and makes it possible to visualize independently edges aligned along different directions.
© 2015 Macmillan Publishers Limited. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ Received 01 April 2015; Accepted 08 July 2015; Published 25 August 2015. Contributions: M.M. and C.D. conceived the imaging concept. M.M. performed the experimental, theoretical and numerical studies. C.D. provided guidance and contributed to the analysis of the results. M.M. and C.D. contributed to the writing of the manuscript. The authors declare no competing financial interests.
Submitted - 1501.02406
Supplemental Material - ncomms9037-s1.pdf
Published - ncomms9037.pdf