Centre for Nondestructive Evaluation and Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, 600036, Tamil Nadu, India.
Sci Rep. 2017 Aug 10;7(1):7777. doi: 10.1038/s41598-017-08036-4.
This paper reports the experimental demonstration of deep subwavelength ultrasonic imaging of defects in metallic samples with a feature size of λ/25 using holey-structured metamaterial lenses. Optimal dimensions of the metamaterial's geometric parameters are determined using numerical simulation and the physics of wave propagation through holey lenses. The paper also shows how the extraordinary transmission capacity of holey structured metamaterials comes about by the coupling of higher frequencies in the incident ultrasonic wave field to resonant modes of the lens.
本文报道了使用具有 λ/25 特征尺寸的周期性开口结构超材料透镜实现对金属样品中缺陷的深亚波长超声成像的实验验证。通过数值模拟和波在有孔透镜中传播的物理特性确定了超材料的几何参数的最佳尺寸。本文还展示了通过将入射超声波场中的高频耦合到透镜的共振模式，实现了周期性开口结构超材料的非凡透射能力。
