Quantum Nanophotonics with Energetic Particles:X-rays and Free Electrons (2411.09019v1)

Abstract: Rapid progress in precision nanofabrication and atomic design over the past 50 years has ushered in a succession of transformative eras for molding the generation and flow of light. The use of nanoscale and atomic features to design light sources and optical elements-encapsulated by the term nanophotonics-has led to new fundamental science and innovative technologies across the entire electromagnetic spectrum, with substantial emphasis on the microwave to visible regimes. In this review, we pay special attention to the impact and potential of nanophotonics in a relatively exotic yet technologically disruptive regime: high-energy particles such as X-ray photons and free electrons-where nanostructures and atomic design open the doors to unprecedented technologies in quantum science and versatile X-ray sources and optics. As the practical generation of X-rays is intrinsically linked to the existence of energetic free or quasi-free-electrons, our review will also capture related phenomena and technologies that combine free electrons with nanophotonics, including free-electron-driven nanophotonics at other photon energies. In particular, we delve into the demonstration and study of quantum recoil in the X-ray regime, the study of nanomaterial design and free-electron wave shaping as means to enhance and control X-ray radiation, examine the free-electron generation enabled by nanophotonics, and analyze the high-harmonic generation by quasi-free electrons. We also discuss applications of quantum nanophotonics for X-rays and free electrons, including nanostructure waveguides for X-rays, photon pair enhanced X-ray imaging, mirrors, and lenses for X-rays, among others.

• The paper presents a comprehensive review of quantum nanophotonic interactions, emphasizing free-electron-driven X-ray generation and quantum recoil effects.
• It details innovative electron wavefunction engineering techniques that tailor X-ray emission and lower the thresholds for high-harmonic generation.
• The review outlines promising applications in quantum sensing, imaging, and computing, showcasing the impact of precise nanostructure design on light-matter interactions.

Quantum Nanophotonics with Energetic Particles: X-rays and Free Electrons

The paper "Quantum Nanophotonics with Energetic Particles: X-rays and Free Electrons" presents an extensive review of recent advancements in quantum nanophotonics, focusing specifically on the interactions between free electrons and X-rays with nanostructures. The work discussed in this review is pivotal as it opens new avenues for manipulating light-matter interactions at unprecedented energy scales, primarily facilitated by nanoscale and atomically designed structures.

Significant progress has been made in the field due to advances in nanofabrication and atomic design, which have enabled precise control over light generation and propagation. This paper explores the integration of free-electron dynamics with nanophotonics, particularly under high-energy regimes like X-rays, exploring the opportunities and phenomena arising from such interactions.

Key Areas of Exploration

1. Quantum Phenomena in Free-Electron-Driven X-ray Generation: The review highlights quantum recoil effects, where discrepancies between classical and quantum predictions of photon energy shifts are significant in X-ray emission from free electrons interacting with nanostructures. These observations underscore the relevance of quantum mechanics in understanding free-electron interactions with periodic atomic structures, contributing to phenomena such as Smith-Purcell and parametric X-ray radiation.
2. Free-Electron Waveshaping: Electron wavefunction engineering is identified as a potent method to enhance and control X-ray radiation. By manipulating the spatial and temporal characteristics of electron beams, it becomes possible to tailor the radiation emitted in non-trivial ways, thus providing a pathway to novel quantum light sources.
3. High-Harmonic Generation (HHG): The paper reviews how high-harmonic generation of extreme ultraviolet and X-rays is enhanced by nanostructures. Nanophotonics offers a promising platform to lower the intensity thresholds required for HHG while enabling new emission patterns through structural tuning.
4. X-ray Waveguides: X-ray waveguide nanophotonics is explored as a means to further control light at small scales. This includes advancements in waveguide fabrication and applications in coherent imaging and quantum optics experiments. The guided modes within these waveguides can interact with atomic emitters, giving rise to unique emission characteristics and potential coherence enhancements.
5. Applications in Quantum Information and Sensing: The review speculates on the potential applications of these interactions in quantum sensing, where free electrons could serve as quantum probes due to their unique spatial and temporal coherence properties. Nanophotonic-enhanced scintillators and novel X-ray sources are poised to have substantial impacts on fields like medical imaging, particle detection, and fundamental quantum optics experiments.

Implications and Future Prospects

The implications of this review are profound both practically and theoretically. Practically, the enhancement of X-ray and extreme ultraviolet sources could lead to more compact, efficient, and tunable light sources, revolutionizing fields such as imaging and spectroscopy. Theoretical implications include a deeper understanding of quantum electrodynamics at the nanoscale, facilitating further exploration of light-matter interactions with high precision.

The paper outlines the promise of quantum nanophotonics in developing new technologies that harness the unique properties of quantum states and structured light. The ability to generate specific quantum states through precise free-electron manipulation opens avenues for future innovations in quantum computing and information processing, particularly leveraging the fast and localized nature of such interactions.

In conclusion, this comprehensive review encapsulates the significant advancements having been made in the integration of quantum nanophotonics with free-electron dynamics. It acts as a crucial resource for researchers aiming to navigate the complex yet promising landscape of high-energy photonics and its applications in modern scientific and technological paradigms. Future developments are likely to continue exploring how nanostructural intricacies can be optimized for even more efficient and tailored light-matter interactions.