基于孔洞结构超材料的涂层亚表面微细缺陷高实时超分辨率声学成像基础研究

本项目旨在探究利用孔洞结构超材料的倏逝波增强效应对涂层亚表面微细缺陷实施高实时和超分辨率声学成像的理论与方法。以近场声波调控理论为引领，在揭示深亚波长尺度下倏逝波特性和孔洞结构超材料内部倏逝波增强机制的基础上，突破涂层亚表面检测声场的靶向精准合成、倏逝回波的快速高灵敏度宽频传感和倏逝波逆时偏移成像等三大关键技术。同时，采用宽域快速成像和局域精细显微策略，有效协调实时成像与完备定量表征之间的矛盾，发展一种基于孔洞结构超材料的高实时和超分辨率声学成像方法，实现涂层亚表面微细缺陷的高性能定量化无损检测。.创新之处在于：1）创建深亚波长尺度下倏逝波特性理论分析基础，精准靶向合成涂层亚表面的检测声场；2）揭示超材料内部倏逝波增强机制，首创实现基于孔洞结构超材料的倏逝波高灵敏度宽频传感；3）提出宽域快速成像和局域精细显微的复合策略，基于倏逝波逆时偏移反演，创新实现一种高实时和超分辨率的声学成像方法。

This project aims to explore real-time and super-resolution acoustic imaging of subsurface micro-sized defects in coatings by exploiting the evanescent amplification inside a holey-structured acoustic metamaterial. According to the theory on acoustic wave manipulations in the near field, we theoretically investigate the wave interaction with subsurface defect and the underlying mechanism of evanescent amplification inside the holey-structured metamaterial. Furthermore, we develop the key technologies on the accurate synthesis of acoustic probing field, rapid acquisition of evanescent waves with broadband sensor array, and evanescent waveform inversion with reverse time migration algorithm. Meanwhile, a strategy combining rapid detection over wide area and accurate characterization within small region is proposed to compromise the contradiction between real-time imaging and quantitative evaluation. With these results, a new imaging method is realized with the holey-structured acoustic metalens, which is capable of real-time and super-resolution characterization of subsurface micro-sized defects in coatings..The novelties of this project embody: 1) Establishing a theoretical basis for the analysis of evanescent wave dynamics and synthesis of acoustic probing field in coatings; 2) Revealing the underlying mechanism of evanescent amplification inside the holey-structured metamaterial, achieving broadband and ultrasensitive detection of evanescent waves for the first time; 3) Propose a real-time and super-resolution acoustic imaging method with evanescent reverse time migration and an imaging strategy that combines rapid detection over wide area and accurate characterization within small region.