梯度声子晶体特性及应用

The richness of dispersion bands in phononic crystal (PC) allows the manipulation of acoustic/elastic waves at the scale of wavelength in various unprecedented ways. At present, the two conventional ways to design dispersion bands of the PC, i.e., by changing the structural and/or material parameters, can not satisfy the every-increasing requirements for applications anymore.Introduction of gradient in PC can achieve new degrees of freedom in the designing of the PC's dispersion bands and greatly enhance the wave manipulation power of PC.In this project, we will thoroughly explore all possible ways that the gradint can be introduced, and will give systematical investigations to the influence of the gradient-introcucing on the band structure of PC. In additon, we will realize various new effects by graded PCs, such as focusing, imaging and illusion of sonic waves, and we will design new pplications and fabricate new devices based on these new effects. This project can be expected to discover new phenomena, to introduce new concepts and to predict new applications, thus it is of scientific significance and applicative value.

声子晶体以其丰富的色散关系带来多种前所未有的方式来实现在波长尺度对声波与弹性波的人工操控。目前，在声子晶体带结构的人工设计中，仅仅通过调节晶体的几何排列方式和/或晶体组元的材料参数这两种传统手段已不能满足应用上的新需求。声子晶体中梯度的引入将拓展其色散关系的调节自由度，极大地增强其对声波和弹性波的人工操控能力。本项目将深入探索声子晶体中梯度的所有可能引入方式，系统研究其色散性质同梯度的关系，利用梯度声子晶体实现各种新奇效应，如声波的汇聚、成像、幻象效应等，设计并最终在实验上实现新型梯度声子晶体功能器件。这些研究将有助于提出新概念、发现新现象和预期新应用，具有科学意义和应用价值。

本项目中我们通过在声子晶体中引入梯度、杂化等方式来拓展声子晶体色散调节自由度以实现对声波的连续操控以及精细调控，利用梯度声子晶体、杂化声子晶体等结构实现各种新奇声学效应，并利用这些新效应设计新型梯度声子晶体功能器件。我们利用梯度声子晶体、杂化声子晶体等结构实现了声波的多像点可控成像、声波的柔性传输、界面态反常声透射等多种新奇声学效应，实现了自准直声束的海市蜃楼效应、大角度拐弯效应以及分波效应等精细调控方式，设计了梯度多边形声子晶体共振腔、梯度波导定向声发射器、梯度表面结构固体板粒子声操控等声波功能器件。我们相信，项目中取得的这些研究结果将有助于进一步加强声子晶体的声操控能力，为利用梯度声子晶体结构设计各种声学器件提供一些有益的指导。