局域共振型声学超材料机理探讨  

Mechanism for local resonant acoustic metamaterial

作　　者：刘娇[1] 侯志林[1] 傅秀军[1] 

机构地区：[1]华南理工大学物理系,广州510640

出　　处：《物理学报》2015年第15期261-268,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11274121)资助的课题~~

摘　　要：本文以二维固体薄板中的弹性波传播为例,对基于共振子结构的声学超材料带隙机理进行了探讨,证明在声学超材料中带隙形成既与共振子对波的散射相位有关,也与波在共振体之间的几何传播相位有关.通过调节散射相位和几何传播相位均能实现对色散关系的调控.基于这一理解,探究了弹性波超材料中的次波长缺陷态和负折射现象的实现条件.Taking the flexural wave propagating in elastic thin plate as an example, we investigate the mechanism for gap opening in the resonator-based acoustic metamaterials. Results show that the band gap in such a kind of structure depends not only on the abrupt phase change of the wave when it is scattered by the resonators, but also on the retarded phase of wave when it is propagating in host. This means that the dispersion of wave in the structure can be adjusted either by the scattering or by the propagating phase. Based on this understanding, we show that the defect state at subwavelength scale（obtained either by changing locally the resonating property of the resonator or by changing locally the distance between the resonators） can be understood simply by the band gap condition. We show further in this paper that, because the dispersion of the metamaterial can be adjusted by the propagating phase, the structures with negative band at a subwavelength scale can also be achieved by arranging the resonators into a compound lattice.

关 键 词：声学超材料 负折射 缺陷态 

分 类 号：TB34[一般工业技术—材料科学与工程]