Experiments on Maxwell's fish-eye dynamics in elastic plates

• Published in: Applied Physics Letters
• Main Authors: Lefebvre, Gautier, Dubois, Marc, Beauvais, Romain, Achaoui, Younes, Ing, Ros Kiri, Guenneau, Sébastien, Sebbah, Patrick
• Other Authors: Direction générale de l'armement, Groupe de Recherche Mesoimage, European Research Council (ERC), Agence Nationale de la Recherche (L' Agence Nationale de la Recherche)
• Format: Article in Journal/Newspaper
• Language: English
• Published: AIP Publishing 2015
• Subjects: Physics and Astronomy (miscellaneous); North Pole; South Pole; South pole
• Online Access: http://dx.doi.org/10.1063/1.4905730; https://pubs.aip.org/aip/apl/article-pdf/doi/10.1063/1.4905730/14094863/024101_1_online.pdf

We experimentally demonstrate that a Duraluminium thin plate with a thickness profile varying radially in a piecewise constant fashion as h(r)=h(0)(1+(r/Rmax)2)2, with h(0) = 0.5 mm, h(Rmax) = 2 mm, and Rmax = 10 cm, behaves in many ways as Maxwell's fish-eye lens in optics. Its imaging properties for a Gaussian pulse with central frequencies 30 kHz and 60 kHz are very similar to those predicted by ray trajectories (great circles) on a virtual sphere (rays emanating from the North pole meet at the South pole). However, the refocusing time depends on the carrier frequency as a direct consequence of the dispersive nature of flexural waves in thin plates. Importantly, experimental results are in good agreement with finite-difference-time-domain simulations.