声学超材料超分辨成像

Super-resolution imaging of acoustic metamaterials

声学衍射现象作为声波的固有属性,是声学成像的理论基础。Abbe衍射分辨率极限理论和瑞利判据限制了传统声学成像系统的分辨率。成像分辨率的限制主要是携带成像物体高频信息的倏逝波在垂直分界面方向上指数衰减,更为清晰的成像物体信息在远场不能有效采集成像,从而形成了衍射极限。为了突破这种衍射极限,人们在获取倏逝波所携带的高频细节信息方面进行了研究。针对声学超分辨成像的研究发展,介绍了几种具有代表性的不同结构声学超透镜,包括基于共振型声学超透镜、非共振型声学超透镜和超振荡型声学超透镜。简述了以上声学超透镜的基本原理和功能特点,并对声学超分辨聚焦的应用前景进行了展望。

Acoustic diffraction,as an inherent property of acoustic wave,is theoretical foundation for the conventional acoustic imaging.Abbe diffraction limit theory and Rayleigh criterion limit the resolution of traditional acoustic imaging system.The main reason of the limitation of imaging resolution is that the evanescent wave carrying high frequency information decays exponentially in the vertical interface,it cannot be effectively acquired in the far field.In order to break through this diffraction limit,research has been conducted on how to obtain the high-frequency details carried by evanescent waves.Several representative acoustic superlens for acoustic super-resolution imaging are introduced,mainly including resonance acoustic superlens,non-resonance surperlens,and super-oscillation acoustic superlens.The basic principles and functional characteristics of the above research contents are briefly described,and the application prospect of acoustic super-resolution focusing is prospected.