Collaborative Research: Implementing Topologically Protected Gigahertz Acoustic Circuits

微波声器件在无线通信技术和量子信息科学中有着广泛的应用。该NSF项目旨在实现传播损耗比传统工程电路更低的声学器件。该项目将给以千兆赫兹频率运行的低损耗声学系统的设计和特性带来变革性的变化。这将通过实现拓扑电子态的声学模拟并用网络分析和微波显微镜来表征它们来实现。该项目的智能优点包括：(1)具有非平凡拓扑结构的声学器件的设计；(2)复杂结构中声传输的模拟；(3)先进微波电路的制造；(4)压电膜上波传播的纳米可视化。该项目的更广泛影响包括(1)为无线通信应用实施实用设备，(2)在两个机构实施综合研究和教育计划，以获得最佳的培训和学习体验，(3)面向当地高中生和教师，重点关注代表不足的/少数群体，以及(4)促进当地K-12学生夏令营的有效性。从凝聚态物理学中汲取灵感，有可能设计出拓扑上不平凡的声子系统，在这种系统中，声波可以在没有后向散射的情况下传播。然而，由于制作上的挑战和缺乏合适的表征工具，声学拓扑超材料大多是在千赫到兆赫的工作频率下展示的。这个NSF项目旨在通过理论分析、数值模拟、器件制造和纳米级可视化相结合的方法来实现具有拓扑保护的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测和改进是至关重要的。这样的设计验证循环将加快基于量子谷霍尔、量子自旋霍尔或类似量子霍尔效应的声学元件的原型制作，如波导、延迟线、分频器/组合器、谐振器、频分复用器和滤波器。将在这两个机构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向当地高中生和教师进行推广。积极参与前沿研究将影响他们在STEM领域的职业道路。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.