Collaborative Research: Implementing Topologically Protected Gigahertz Acoustic Circuits

微波声学器件广泛应用于无线通信技术和量子信息科学。该 NSF 项目旨在实现比传统设计电路传播损耗更低的声学器件。该项目将为在千兆赫兹范围内运行的低损耗声学系统的设计和表征带来革命性的变化。这将通过实现拓扑电子态的声学模拟并通过网络分析和微波显微镜对其进行表征来实现。该项目的智力优势包括（1）具有重要拓扑结构的声学设备的设计，（2）复杂结构中声学传输的模拟，（3）先进微波电路的制造，以及（4）压电膜上波传播的纳米级可视化。该项目的更广泛影响包括 (1) 实施无线通信应用的实用设备，(2) 两个机构的综合研究和教育计划，以实现最佳的培训和学习体验，(3) 向当地高中生和教师进行宣传，重点关注代表性不足/少数群体，以及 (4) 提高 K-12 学生当地夏令营的有效性。在超高频和超高频领域，传统声学设备面临带宽窄和传播损耗高的问题。从凝聚态物理学中汲取灵感，可以设计出拓扑上非平凡的声子系统，其中声波可以传播而不会被反向散射。然而，由于制造方面的挑战和缺乏适当的表征工具，声学拓扑超材料大多以千赫兹到兆赫兹的工作频率进行演示。该 NSF 项目旨在通过结合理论分析、数值模拟、器件制造和纳米级可视化，实现具有拓扑保护声子传输的千兆赫声学集成电路。特别是，纳米级声场的直接信息对于新型微波电路的检查和改进至关重要。这样的设计验证循环将加快声学元件的原型设计，例如波导、延迟线、分配器/组合器、谐振器、频分复用器以及基于量子谷霍尔、量子自旋霍尔或类量子霍尔效应的滤波器。两个机构将建立综合研究和教育项目，以便培训学生掌握现代纳米制造技术、最先进的微波声学系统和扫描探针显微镜。研究团队将通过实验室体验、周六研讨会和夏令营来接触当地高中生和教师。积极参与前沿研究将影响他们走向 STEM 领域的职业道路。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Microwave acoustic devices are widely used in wireless communication technology and quantum information science. This NSF project aims to realize acoustic devices with lower propagation loss than traditionally engineered circuits. The project will bring transformative change to the design and characterization of low-loss acoustic systems operating in the gigahertz regime. This will be achieved by implementing the acoustic analogues of topological electronic states and characterizing them with network analysis and microwave microscopy. The intellectual merits of the project include (1) design of acoustic devices with nontrivial topology, (2) simulation of acoustic transport in complex structures, (3) fabrication of advanced microwave circuits, and (4) nanoscale visualization of wave propagation on piezoelectric membranes. The broader impacts of the project include (1) implementation of practical devices for wireless communication applications, (2) integrated research and education programs in both institutions for optimal training and learning experience, (3) outreach to local high-school students and teachers with a strong focus on underrepresented/minority groups, and (4) promoting the effectiveness of local summer camps for K-12 students.In the Ultra High Frequency and Super High Frequency regime, conventional acoustic devices suffer from narrow bandwidth and high propagation loss. Drawing inspiration from condensed matter physics, it is possible to design topologically nontrivial phononic systems, where acoustic waves can propagate without being backscattered. Due to the challenge in fabrication and the lack of appropriate characterization tools, however, acoustic topological metamaterials are mostly demonstrated with kilohertz to megahertz operating frequencies. This NSF project aims to implement gigahertz acoustic integrated circuits with topologically protected phononic transport by combining theoretical analysis, numerical simulation, device fabrication, and nanoscale visualization. In particular, the direct information on nanoscale acoustic fields is expected be crucial for the inspection and refinement of novel microwave circuitry. Such a design-validation loop will expedite the prototyping of acoustic elements such as waveguides, delay lines, dividers/combiners, resonators, frequency division multiplexer, and filters based on quantum valley Hall, quantum spin Hall, or quantum-Hall-like effects. Integrated research and education programs at both institutions will be established so that students are trained to master modern nanofabrication techniques, state-of-the-art microwave acoustic systems, and scanning probe microscopy. The research teams will outreach to local high school students and teachers through lab experience, Saturday workshop, and summer camps. The active involvement in frontier research will influence their career path towards STEM fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.