声学成像是一种用来检测物质结构和成分的重要方法,其分辨率受限于衍射极限(diffraction limit)。为了获取更高的分辨率,往往需要测量高空间频率的声倏逝波(acoustic evanescent wave)。倏逝波带有物体的细节特征信息,离开天然材料物体后的衰减特性满足指数关系。近年来,科学家利用结构声学超常材料(structured acoustic metamaterials,AMM)克服衍射极限,通过增强倏逝波 Acoustic imaging is an important method for detecting the structure and composition of matter, and its resolution is limited by the diffraction limit. In order to obtain higher resolution, it is often necessary to measure acoustic evanescent waves at high spatial frequencies. Evanescent waves have the characteristic feature information of the object, and the extinction property of the natural material object exponentially. In recent years, scientists have used structural acoustic metamaterials (AMM) to overcome the diffraction limit by enhancing the evanescent wave