声学宽带多焦点聚焦  

Broadband multi-focus sound focusing

作　　者：范旭东[1] 朱一凡[1] 袁樱[2] 梁彬[1] 邹欣晔[1] 杨京[1] 程建春[1] 

机构地区：[1]南京大学微结构协同创新中心近代声学教育部重点实验室南京大学声学研究所,南京210093 [2]江苏理工学院数理学院,常州213001

出　　处：《声学学报》2016年第5期613-619,共7页Acta Acustica

基　　金：国家重点基础研究发展计划项目(973计划)(2011CB707900;2012CB92150);国家自然科学基金项目(11174138;11174139;11222442;81127901;11274168);NCET-12-0254;江苏高校优势学科建设工程

摘　　要：针对声学宽带多焦点聚焦的问题,设计出结构简洁的声学人工结构。通过控制细槽深度,对反射声波的波前进行任意操控。数值仿真结果验证了所设计的声人工结构的聚焦效果。这种人工结构还允许对焦点的相对位置及数目进行精确而自由的调控,当尺寸大于波长的障碍物存在时仍可通过合理设计来产生聚焦效果。该方案具有设计简洁及焦点可控等优点,有望在生物医学及无损检测等场合产生广泛应用。An acoustical metastructure is proposed to focus reflected wave into multiple focus in a broad band. This metastructure has a simple configuration and planar shape, consisting of an array of groove-like metamaterial units with subwavelength width. The method of harnessing the convergence of reflected wave by controlling the local phase response is proposed. An analytical expression of the parameter distribution for realizing broadband focusing at given loci is derived, which can be used to precisely design the acoustic metastructure capable with broadband multi-focus focusing. The performance of the designed metastructure is demonstrated via numerical simulations, showing that the metastructure is able to converge the acoustic energy of incident wave into the preset multiple focus. This scheme enables free and precise control of the number and relative locations of loci, and can be designed to yield desired focusing effect even in the presence of obstacles with sizes comparable to the working wavelength. With the merits of simple fabrication and tunable focus, our design may be applicable to many important situations such as medical ultrasound and non-destructive tests

关 键 词：多焦点 聚焦 声学 宽带 仿真结果 相对位置 无损检测 生物医学 

分 类 号：O422[理学—声学]