Wave Physics of Complex Mesoscopic Materials

复杂介质中的波具有显著的特性，其中许多波是由强烈的多次散射引起的，这继续挑战着我们对波物理的基本理解。这门学科是许多科学和工程学科的基础，这些学科依赖基于波的成像和材料表征技术。波在复杂介质中的传输对我们的繁荣也是至关重要的，因为它影响到例如我们想象复杂结构(例如混凝土桥梁和技术设备的缺陷)以及有效勘探和开采自然资源的能力。我的研究计划的目标是在我的实验室的最新进展的基础上，解决复杂的强散射材料的波物理中最重要的悬而未决的问题，并基于我们对波散射的知识开发和使用新的技术来探索它们的结构和动力学。为了实现这些目标，我的学生、博士后研究员和我将进行最先进的超声波实验，使用我们首创的技术，这些技术被国际公认为解决该领域许多关键挑战的最有效的方法。我们的方法有许多独特的优势：能够记录关于波传输的完整信息，可以进行超声波测量的空间、时间和频率的出色分辨率，研究具有精确确定的结构的材料的可行性，所涉及的长度和时间的方便范围，以及使用新的理论模型成功解释我们的数据的可能性。我们将研究的有趣的波现象的例子包括安德森定域化(由于无序导致的波的最终捕获)和由于负折射和拓扑效应而产生的人工结构材料(声子晶体和超材料)的显著性质。我们还将开发复杂介质的动态成像方法(其中传统成像技术无法实现)，从而产生用于材料表征和过程控制的新型超声波光谱仪。我们将使用这些技术来研究多孔和颗粒状材料、具有深度亚波长结构的超材料、泡沫、泡沫凝胶和充气模型食品生物材料。波动行为在巨大的波长和波动类型范围内的普遍性意味着，我们的研究的影响预计将远远超出超声波，从而促进其他研究领域的进步。

Waves in complex media exhibit remarkable properties, many of which result from strong multiple scattering and which continue to challenge our basic understanding of wave physics. This subject underpins many scientific and engineering disciplines that rely on wave-based techniques for imaging and materials characterization. The transport of waves through complex media is also fundamental to our prosperity, as it affects, for example, our ability to image complex structures (e.g., defects in concrete bridges and technological devices) and to effectively prospect for and extract natural resources. The goals of my research program are to build on recent progress in my laboratory to address the most important unresolved questions in the wave physics of complex strongly scattering materials, and to develop and use new techniques, based on our knowledge of wave scattering, to probe their structure and dynamics. To achieve these objectives, my students, postdoctoral fellow and I will perform state-of-the-art ultrasonic experiments, using techniques that we have pioneered and that are recognized internationally as some of the most powerful approaches to addressing many key challenges in the field. Our approach has many distinct advantages: the ability to record complete information about wave transport, the excellent resolution in space, time and frequency with which ultrasonic measurements can be performed, the feasibility of studying materials with precisely determined structures, the convenient range of lengths and times involved, and the likelihood of success in interpreting our data using new theoretical models. Examples of intriguing wave phenomena that we will investigate include Anderson localization (the ultimate trapping of waves due to disorder) and the remarkable properties of artificially structured materials (phononic crystals and metamaterials) due to negative refraction and topological effects. We will also develop dynamic imaging methods for complex media (in which traditional imaging techniques fail), leading to new ultrasonic spectroscopies for materials characterization and process control. We will use these techniques to study porous and granular materials, metamaterials with deeply subwavelength structures, foams, bubbly gels, and aerated model food biomaterials. The universality of wave behaviour across a huge range of wavelengths and wave types implies that the impact of our research is expected to extend well beyond ultrasonics, facilitating advances in other fields of research.