Harnessing negative refraction and evanescent waves toward super-resolution Lamb wave imaging
Harnessing negative refraction and evanescent waves toward super-resolution Lamb wave imaging
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DOI：
10.1063/5.0152717
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发表时间：
2023-07
影响因子：
4
通讯作者：
H. Danawe;S. Tol
中科院分区：
文献类型：
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作者：
H. Danawe;S. Tol
数值模拟和实验验证了最低反对称（A0）模兰姆波在薄铝板中的超分辨聚焦。利用声子晶体（PC）晶格的各向异性和倏逝波的放大实现了亚波长聚焦/成像。为此，我们在铝板中嵌入了一个PC平面透镜，该透镜由以正方形网格形式排列的孔组成。我们发现，束缚板声子模式放大倏逝波，如以前观察到的电磁波和声波。因此，平板模式有助于通过PC透镜传播亚波长信息，以到达由于负折射而形成的近场图像，并导致高分辨率图像。
We numerically and experimentally demonstrate super-resolution focusing of the lowest anti-symmetric (A0) mode Lamb waves in a thin aluminum plate. The subwavelength focusing/imaging is achieved by exploiting the anisotropy in phononic crystal (PC) lattices and amplification of evanescent waves. To this end, we embedded a PC flat lens in the aluminum plate, consisting of holes arranged in a square lattice formation. We revealed that the bound slab phonon modes amplify evanescent waves, as previously observed for electromagnetic and acoustic waves. Hence, the slab mode helps propagate subwavelength information through the PC lens to reach the near-field image formed due to negative refraction and result in the high resolution image.