Collaborative Research: Quantum-Coherent Interactions between Free and Guided Electrons and Photons

点击翻译按钮获取中文摘要

General audience abstract:When a stream of electrons in free space passes over a patterned surface, light is produced. Over the past century, scientists and engineers have used this process to power applications ranging from satellite communications to microwave ovens. Although these electron-driven light sources have proven successful in numerous applications, some of the microscopic, quantum physics underlying these sources has remained poorly understood. As a result, we do not yet know the fundamental limits of this technique. In this project, the detailed, quantum-mechanical nature of the interactions between free-space electrons, patterned (or structured) surfaces, and light waves will be uncovered. Specifically, in this work, single electrons, traveling through vacuum over specially designed surfaces patterned at the nanometer length scale, will be used to generate single photons; and the resulting interconnected, so-called entangled, quantum states will be studied. The findings from this work could impact emerging applications in quantum computing, quantum communication, and quantum sensing by providing efficient, low-noise, and tunable sources of single electrons and single photons, as well as sources of unique quantum states of photons. Beyond the broader scientific impact of this work, this program will also contribute to the training of undergraduate and graduate researchers. Additionally, the effort will include summer internships for high-school students and develop a student-led seminar series that will improve the mentoring, organizational, and leadership skills of the students supported by this program.Technical audience abstract:When low-energy free electrons (few to tens of keV) interact with nanostructured materials, electromagnetic radiation, from the terahertz to the visible domain, can be produced. Recently, researchers have investigated the quantum-coherent nature of free electrons after interacting with classical light in the vicinity of nanoscale objects and surfaces. In this project the complete quantum nature of the interactions between free electrons, light, and nanostructured materials will be explored. Specifically single electrons will generate single photons via an interaction mediated by tailormade nanostructures, and the quantum-coherent properties of the electrons and photons will be experimentally probed. The project will consist of four experimental efforts: (1) The study of the coupling of single photons to a passing free electron and the use of this coupling for the development of heralded single-photon and single-electron sources; (2) The investigation of the quantum coherence of this single-photon-single-electron coupling by using multiple interaction structures for the generation of Bell states; (3) The extension of the quantum-coherent electron-photon interaction via nanostructured electron-beam waveguides in which quantum efficiencies approaching and exceeding unity should be achievable; and (4) The study of multiple photon-generation interactions in this high-efficiency regime within guided electron beam systems to generate both isolated and entangled sets of large-photon-number Fock states. This work will lead to advanced free-electron and photon sources for quantum information science and technology and quantum-enhanced free-electron and optical metrology. The ability to use photons to herald electron arrival would enable shot-noise-free electron sources for low-dose electron microscopy, improved electron beam lithography, and quantum-enhanced free-electron metrology. Furthermore, the quantum-coherent electron-photon interactions studied in this work may additionally provide a viable path for the compact generation of highly-entangled photon states.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.