声子晶体平板组合成像特性分析

用多重散射方法分析了声子晶体单平板和多平板的成像特性。发现：在特定频率范围内，引入等效负折射率后，单板负折射成像可用反Snell定律描述；多层声子晶体平板成像服从依次成像规律，可类比传统几何光学中共轴球面系统的成像，引入实物实像、虚物虚像等概念；平板透镜不改变出射波的出射方向，仅使出射位置产生平移；多平板透镜的累加成像与等厚度的单一平板透镜成像具有相同的效果。平板透镜的这些成像特点，使其在成像质量、加工方法、系统组合等方面比球面透镜更具优势。

Characteristics analysis for imaging process of a phononic crystal combined slabs system

With the multiple-scattering theory(MST),the imaging features of a phononic crystal slab and slabs were investigated.It was found that there is a negative refraction imaging for a single slab in a certain frequency range,the imaging can be described with Anti-Snell’s law after introducing an equivalent negative refraction rate;for slabs,the image can be obtained by repeating imaging according to position order of slabs,its processing is similar to the case of a conventional geometric optical system of spherical surfaces with the same primary optical axis,so the concepts,such as,real/ virtual object and image etc,can also be employed;an acoustic slab lens can not change the propagating direction of sound wave in phononic crystal but shift its locations;a combined slabs system has the same imaging result as that of a single slab when its cumulated thickness is equal to the thickness of the single slab.These characteristics made a combined slabs lens system superior to a traditional geometric optical spherical surface system in imaging quality,lens manufacturing and system constructing etc.