Structured Electron Interferometry

该项目的目标是启用和扩展量子激发的电子测量。量子测量和量子信息技术的绝大多数现代发展都使用光子（光的最小单位）作为核心组成部分。然而，光子的类波性质仍然对这一理论的最小应用范围设置了基本的限制。这些量子测量协议中的许多也可以用物质波来实现，但是用于生成、操纵、应用和检测物质波的技术并不像光子那样发达。本项目开发电子显微镜中的新量子技术，如使用电子的无相互作用测量，并将其应用于探索纳米尺度上的各种现象。这将提供新的量子电子显微镜工具，可用于减小量子器件的尺寸，类似于传统电子显微镜如何减小经典计算组件的尺寸。除了为高级显微镜和纳米科学的研究生和本科生提供培训外，该项目还将吸引第一年的STEM专业学生，通过向他们介绍编程，数据分析，电子显微镜，纳米纤维和光学物理，在夏季为他们提供进入第二年的“桥梁”。该项目开发和使用工具来制备和测量电子显微镜内自由电子波函数的相干性和相位。纳米级衍射全息图提供了一种方法来相干操纵个别电子的相位分布以及测量它们。例如，衍射全息图可以产生具有螺旋相位分布的自由电子波函数，这为探测纳米等离子体的手性和空间相干性提供了一种新的方法。电子透明相位光栅还可以作为电子的优化分束器，在该项目中用于创建具有大路径间隔的电子干涉仪，用于测量纳米级的电场和磁场。还探讨了无相互作用的测量协议，这可以使容易损坏的材料的高分辨率电子显微镜。该项目与广泛的科学和应用相联系，为一系列学科和行业的项目参与者提供了独特的机会。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的评估被认为值得支持影响审查标准。

The goal of this project is to enable and expand quantum-inspired measurements with electrons. The vast majority of modern developments in quantum measurement and quantum information technologies use photons, the smallest unit of light, as a central component. Yet the wavelike nature of photons still places fundamental limits on the smallest lengthscale at which this can be applied. Many of these quantum measurement protocols can be implemented with matter waves as well, but the technologies used to generate, manipulate, apply, and detect matter waves are not as well-developed as those for photons. This project develops new quantum techniques in the electron microscope, such as interaction-free measurements using electrons, and applies them to explore various phenomenon at the nanoscale. This will provide new quantum electron microscopy tools that can be used to reduce the size of quantum devices, similar to how conventional electron microscopes enabled the reduction in size of classical computing components. In addition to providing training to graduate and undergraduate students in advanced microscopy and nanoscience, this project will engage first-year STEM majors as well, providing a “bridge” over the summer into their second year by introducing them to programming, data analysis, electron microscopy, nanofabrication, and optical physics. The project develops and uses tools to both prepare and measure coherence and phase of free electron wavefunctions inside electron microscopes. Nanoscale diffraction holograms provide a way to coherently manipulate the phase profile of individiual electrons as well as measure them. For example, diffraction holograms can produce free electron wavefunctions with helical phase profiles that provide a new way to probe the chirality and spatial coherence of nanoscale plasmonics. Electron-transparent phase gratings can also serve as optimized beamsplitters for electrons, which are used in this project to create electron interferometers with large path separation, useful for measuring electric and magnetic fields at the nanoscale. Interaction-free measurement protocols are also explored, which could enable high resolution electron microscopy of easily damaged materials. The project connects with a broad spectrum of sciences and applications, enabling unique opportunities for project participants in a range of disciplines and industries.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.