EFRI NewLAW:: Non-reciprocal Elastic Wave Propagation in dynamically modulated Photo-elastic media

波的传播是一种普遍存在的物理现象，在信息传输、电信或医学成像中使用的技术设备的核心。波的单向传播正在成为一种新的现象，它可能会破坏当前技术使用波的方式。 传统上和直观上，人们期望波在向前或向后的方向上同样好地传播，然而，某些介质可以打破这种对称性。 单向或单向传播，也称为波的非互易传播，将传输限制为仅一个方向。 这种非传统的特性可以实现全新的功能，并最终实现新的技术和设备。该奖项支持基础研究，为开发可支持弹性波非互易传播的固体材料提供所需的知识。类似于电二极管的出现，其中非互易元件形成了现代电子和计算的基础，这项研究将使未来的设备，其操作依赖于处理固体中弹性波传输的信息。这种器件的例子是表面或体声波器件以及电信中使用的光机械系统。这项研究涉及材料科学、力学、光子学和物理学等多个学科。多学科方法将有助于扩大代表性不足的群体在研究中的参与，并对工程教育产生积极影响。该项目将研究固体硫系玻璃和相变材料，作为产生单向传播的表面和体弹性波的平台。硫属化物材料具有大的、快速的和可逆的光弹性效应，由此材料的弹性性质如刚度在光照射时改变。该项目利用时空调制的固体介质的弹性特性，通过动态照明，这是最近出现的一个潜在的通用方法打破对称性，以实现非互易的弹性波在固体内传播。该团队将开发理论，数值和实验方法，以创建一个新的概念和实践框架，用于开发在动态调制弹性结构（如纤维或膜）中具有非常规传播的弹性波。这将包括定义机制，设计和控制参数，以打破弹性波传播方向的对称性，并实现固体介质中的非互易波传播。

The propagation of waves is a ubiquitous physical phenomenon at the heart of technological devices used in information transmission, telecommunication or medical imaging. One-way propagation of waves is emerging as a novel phenomenon that can disrupt ways in which current technologies employ waves. Conventionally and intuitively, one expects waves to propagate equally well in the forward or backward directions, however, certain media can break this symmetry. One-way or unidirectional propagation, also called non-reciprocal propagation of waves, restricts the transmission to only one direction. This unconventional property may enable totally new functionalities and ultimately new technologies and devices. This award supports fundamental research to provide needed knowledge for the development of solid materials that can support non-reciprocal propagation of elastic waves. Similar to the advent of the electrical diode, in which non-reciprocal elements formed the basis for modern electronics and computing, this research will enable future devices, whose operation relies on processing information transported by elastic waves in solids. Examples of such devices are surface or bulk acoustic wave devices as well as opto-mechanical systems used in telecommunication. This research involves several disciplines including materials science, mechanics, photonics and physics. The multi-disciplinary approach will help broaden participation of underrepresented groups in research and positively impact engineering education.The project will investigate solid chalcogenide glasses and phase change materials as a platform to produce surface and bulk elastic waves with unidirectional propagation. Chalcogenide materials possess large, fast, and reversible photo-elastic effects whereby the material elastic properties such as stiffness change upon illumination by light. This project exploits the spatiotemporal modulation of solid media's elastic properties through dynamical illumination, which has recently emerged as a potential universal method of breaking symmetry to achieve non-reciprocal elastic wave propagation within solids. The team will develop the theoretical, numerical and experimental methods to create a new conceptual and practical framework for developing elastic waves with non-conventional propagation in dynamically modulated elastic structures such as fibers or membranes. This will include defining the mechanisms, designs, and control parameters to break the symmetry in the direction of propagation of elastic waves and achieve non-reciprocal wave propagation in solid media.