1
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Akerboom E, Di Giulio V, Schilder NJ, García de Abajo FJ, Polman A. Free Electron-Plasmon Coupling Strength and Near-Field Retrieval through Electron Energy-Dependent Cathodoluminescence Spectroscopy. ACS NANO 2024; 18:13560-13567. [PMID: 38742710 PMCID: PMC11140833 DOI: 10.1021/acsnano.3c12972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/11/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024]
Abstract
Tightly confined optical near fields in plasmonic nanostructures play a pivotal role in important applications ranging from optical sensing to light harvesting. Energetic electrons are ideally suited to probing optical near fields by collecting the resulting cathodoluminescence (CL) light emission. Intriguingly, the CL intensity is determined by the near-field profile along the electron propagation direction, but the retrieval of such field from measurements has remained elusive. Furthermore, the conditions for optimum electron near-field coupling in plasmonic systems are critically dependent on such field and remain experimentally unexplored. In this work, we use electron energy-dependent CL spectroscopy to study the tightly confined dipolar mode in plasmonic gold nanoparticles. By systematically studying gold nanoparticles with diameters in the range of 20-100 nm and electron energies from 4 to 30 keV, we determine how the coupling between swift electrons and the optical near fields depends on the energy of the incoming electron. The strongest coupling is achieved when the electron speed equals the mode phase velocity, meeting the so-called phase-matching condition. In aloof experiments, the measured data are well reproduced by electromagnetic simulations, which explain that larger particles and faster electrons favor a stronger electron near-field coupling. For penetrating electron trajectories, scattering at the particle produces severe corrections of the trajectory that defy existing theories based on the assumption of nonrecoil condition. Therefore, we develop a first-order recoil correction model that allows us to account for inelastic electron scattering, rendering better agreement with measured data. Finally, we consider the albedo of the particles and find that, to approach unity coupling, a highly confined electric field and very slow electrons are needed, both representing experimental challenges. Our findings explain how to reach unity-order coupling between free electrons and confined excitations, helping us understand fundamental aspects of light-matter interaction at the nanoscale.
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Affiliation(s)
- Evelijn Akerboom
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Valerio Di Giulio
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, Castelldefels, 08860 Barcelona, Spain
| | - Nick J. Schilder
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
- Gleb
Wataghin Physics Institute, University of
Campinas, Campinas 13083-859, Brazil
| | - F. Javier García de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, Castelldefels, 08860 Barcelona, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Albert Polman
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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2
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Kumar S, Lim J, Rivera N, Wong W, Ang YS, Ang LK, Wong LJ. Strongly correlated multielectron bunches from interaction with quantum light. SCIENCE ADVANCES 2024; 10:eadm9563. [PMID: 38718122 PMCID: PMC11078178 DOI: 10.1126/sciadv.adm9563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 04/04/2024] [Indexed: 05/12/2024]
Abstract
Strongly correlated electron systems are a cornerstone of modern physics, being responsible for groundbreaking phenomena from superconducting magnets to quantum computing. In most cases, correlations in electrons arise exclusively because of Coulomb interactions. In this work, we reveal that free electrons interacting simultaneously with a light field can become highly correlated via mechanisms beyond Coulomb interactions. In the case of two electrons, the resulting Pearson correlation coefficient for the joint probability distribution of the output electron energies is enhanced by more than 13 orders of magnitude compared to that of electrons interacting with the light field in succession (one after another). These highly correlated electrons are the result of momentum and energy exchange between the participating electrons via the external quantum light field. Our findings pave the way to the creation and control of highly correlated free electrons for applications including quantum information and ultrafast imaging.
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Affiliation(s)
- Suraj Kumar
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Jeremy Lim
- Science, Mathematics and Technology, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Nicholas Rivera
- Department of Physics, Harvard University, Cambridge MA 02138, USA
| | - Wesley Wong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Yee Sin Ang
- Science, Mathematics and Technology, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Lay Kee Ang
- Science, Mathematics and Technology, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Liang Jie Wong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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3
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Liebtrau M, Polman A. Angular Dispersion of Free-Electron-Light Coupling in an Optical Fiber-Integrated Metagrating. ACS PHOTONICS 2024; 11:1125-1136. [PMID: 38523743 PMCID: PMC10958598 DOI: 10.1021/acsphotonics.3c01574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 03/26/2024]
Abstract
Free electrons can couple to optical material excitations on nanometer-length and attosecond-time scales, opening-up unique opportunities for both the generation of radiation and the manipulation of the electron wave function. Here, we exploit the Smith-Purcell effect to experimentally study the coherent coupling of free electrons and light in a circular metallo-dielectric metagrating that is fabricated onto the input facet of a multimode optical fiber. Using hyperspectral angle-resolved (HSAR) far-field imaging inside a scanning electron microscope, we probe the angular dispersion of Smith-Purcell radiation (SPR) that is simultaneously generated in free space and inside the fiber by an electron beam that grazes the metagrating at a nanoscale distance. Furthermore, we analyze the spectral distribution of SPR that is emitted into guided optical modes and correlate it with the numerical aperture of the fiber. By varying the electron energy between 5 and 30 keV, we observe the emission of SPR from the ultraviolet to the near-infrared spectral range, and up to the third emission order. In addition, we detect incoherent cathodoluminescence that is generated by electrons penetrating the input facet of the fiber and scattering inelastically. As a result, our HSAR measurements reveal a Fano resonance that is coupled to a Rayleigh anomaly of the metagrating, and that overlaps with the angular dispersion of second-order SPR at 20 keV. Our findings demonstrate the potential of optical fiber-integrated metasurfaces as a versatile platform to implement novel ultrafast light sources and to synthesize complex free-electron quantum states with light.
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Affiliation(s)
- Matthias Liebtrau
- Center for Nanophotonics, NWO-Institute
AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Albert Polman
- Center for Nanophotonics, NWO-Institute
AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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4
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Li J, Fang Y, Liu Y. Topologically Protected Strong-Interaction of Photonics with Free Electrons. PHYSICAL REVIEW LETTERS 2024; 132:073801. [PMID: 38427867 DOI: 10.1103/physrevlett.132.073801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 01/16/2024] [Indexed: 03/03/2024]
Abstract
We propose a robust scheme of studying the strong interactions between free electrons and photons using topological photonics. Our study reveals that the topological corner state can be used to enhance the interaction between light and a free electron significantly. The quality factor of the topological cavity can exceed 20 000 and the corner state has a very long lifetime even after the pump pulse is off. And thus, the platform enables us to achieve a strong interaction without the need for zero delay and phase matching as in traditional photon-induced near-field electron microscopy (PINEM). This work provides the new perspective that the topological photonic structures can be utilized as a platform to shape free electron wave packets, which facilitates the control of quantum electrodynamical (QED) processes and quantum optics with free electrons in the future.
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Affiliation(s)
- Jing Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Yiqi Fang
- Department of Physics, Universität Konstanz, Konstanz 78464, Germany
| | - Yunquan Liu
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
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5
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Hardy M, Goldberg Oppenheimer P. 'When is a hotspot a good nanospot' - review of analytical and hotspot-dominated surface enhanced Raman spectroscopy nanoplatforms. NANOSCALE 2024; 16:3293-3323. [PMID: 38273798 PMCID: PMC10868661 DOI: 10.1039/d3nr05332f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 01/13/2024] [Indexed: 01/27/2024]
Abstract
Substrate development in surface-enhanced Raman spectroscopy (SERS) continues to attract research interest. In order to determine performance metrics, researchers in foundational SERS studies use a variety of experimental means to characterize the nature of substrates. However, often this process would appear to be performed indiscriminately without consideration for the physical scale of the enhancement phenomena. Herein, we differentiate between SERS substrates whose primary enhancing structures are on the hundreds of nanometer scale (analytical SERS nanosubstrates) and those whose main mechanism derives from nanometric-sized gaps (hot-spot dominated SERS substrates), assessing the utility of various characterization methods for each substrate class. In this context, characterization approaches in white-light spectroscopy, electron beam methods, and scanning probe spectroscopies are reviewed. Tip-enhanced Raman spectroscopy, wavelength-scanned SERS studies, and the impact of surface hydrophobicity are also discussed. Conclusions are thus drawn on the applicability of each characterization technique regarding amenability for SERS experiments that have features at different length scales. For instance, while white light spectroscopy can provide an indication of the plasmon resonances associated with 10 s-100 s nm-scale structures, it may not reveal information about finer surface texturing on the true nm-scale, critical for SERS' sensitivity, and in need of investigation via scanning probe techniques.
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Affiliation(s)
- Mike Hardy
- School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, B15 2TT, UK.
- Centre for Quantum Materials and Technologies, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
| | - Pola Goldberg Oppenheimer
- School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, B15 2TT, UK.
- Healthcare Technologies Institute, Institute of Translational Medicine, Birmingham B15 2TH, UK
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6
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Tang J, Guo Q, Wu Y, Ge J, Zhang S, Xu H. Light-Emitting Plasmonic Tunneling Junctions: Current Status and Perspectives. ACS NANO 2024; 18:2541-2551. [PMID: 38227821 DOI: 10.1021/acsnano.3c08628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Quantum tunneling, in which electrons can tunnel through a finite potential barrier while simultaneously interacting with other matter excitation, is one of the most fascinating phenomena without classical correspondence. In an extremely thin metallic nanogap, the deep-subwavelength-confined plasmon modes can be directly excited by the inelastically tunneling electrons driven by an externally applied voltage. Light emission via inelastic tunneling possesses a great potential application for next-generation light sources, with great superiority of ultracompact integration, large bandwidth, and ultrafast response. In this Perspective, we first briefly introduce the mechanism of plasmon generation in the inelastic electron tunneling process. Then the state of the art in plasmonic tunneling junctions will be reviewed, particularly emphasizing efficiency improvement, precise construction, active control, and electrically driven optical antenna integration. Ultimately, we forecast some promising and critical prospects that require further investigation.
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Affiliation(s)
- Jibo Tang
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Quanbing Guo
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Yu Wu
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Junhao Ge
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Shunping Zhang
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Hongxing Xu
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
- School of Microelectronics, Wuhan University, Wuhan 430072, China
- Henan Academy of Sciences, Zhengzhou, Henan 450046 China
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7
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Wong LWW, Shi X, Karnieli A, Lim J, Kumar S, Carbajo S, Kaminer I, Wong LJ. Free-electron crystals for enhanced X-ray radiation. LIGHT, SCIENCE & APPLICATIONS 2024; 13:29. [PMID: 38267427 PMCID: PMC10808554 DOI: 10.1038/s41377-023-01363-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/26/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024]
Abstract
Bremsstrahlung-the spontaneous emission of broadband radiation from free electrons that are deflected by atomic nuclei-contributes to the majority of X-rays emitted from X-ray tubes and used in applications ranging from medical imaging to semiconductor chip inspection. Here, we show that the bremsstrahlung intensity can be enhanced significantly-by more than three orders of magnitude-through shaping the electron wavefunction to periodically overlap with atoms in crystalline materials. Furthermore, we show how to shape the bremsstrahlung X-ray emission pattern into arbitrary angular emission profiles for purposes such as unidirectionality and multi-directionality. Importantly, we find that these enhancements and shaped emission profiles cannot be attributed solely to the spatial overlap between the electron probability distribution and the atomic centers, as predicted by the paraxial and non-recoil theory for free electron light emission. Our work highlights an unprecedented regime of free electron light emission where electron waveshaping provides multi-dimensional control over practical radiation processes like bremsstrahlung. Our results pave the way towards greater versatility in table-top X-ray sources and improved fundamental understanding of quantum electron-light interactions.
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Affiliation(s)
- Lee Wei Wesley Wong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Xihang Shi
- Solid State Institute and Faculty of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Aviv Karnieli
- School of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, 69978, Israel
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Jeremy Lim
- Science, Mathematics and Technology, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Suraj Kumar
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Sergio Carbajo
- Electrical and Computer Engineering Department, UCLA, 420 Westwood, Los Angeles, CA, 90095, USA
- Physics and Astronomy Department, UCLA, 475 Portola Plaza, Los Angeles, CA, 90095, USA
- SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Ido Kaminer
- Solid State Institute and Faculty of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Liang Jie Wong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
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8
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Dang Z, Chen Y, Fang Z. Cathodoluminescence Nanoscopy: State of the Art and Beyond. ACS NANO 2023; 17:24431-24448. [PMID: 38054434 DOI: 10.1021/acsnano.3c07593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Cathodoluminescence (CL) nanoscopy is proven to be a powerful tool to explore nanoscale optical properties, whereby free electron beams achieve a spatial resolution far beyond the diffraction limit of light. With developed methods for the control of electron beams and the collection of light, the dimension of information that CL can access has been expanded to include polarization, momentum, and time, holding promise to provide invaluable insights into the study of materials and optical near-field dynamics. With a focus on the burgeoning field of CL nanoscopy, this perspective outlines the recent advancements and applications of this technique, as illustrated by the salient experimental works. In addition, as an outlook for future research, several appealing directions that may bring about developments and discoveries are highlighted.
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Affiliation(s)
- Zhibo Dang
- School of Physics, State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, and Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, People's Republic of China
| | - Yuxiang Chen
- School of Physics, State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, and Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, People's Republic of China
| | - Zheyu Fang
- School of Physics, State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, and Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, People's Republic of China
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9
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Bourgeois MR, Nixon AG, Chalifour M, Masiello DJ. Optical polarization analogs in inelastic free-electron scattering. SCIENCE ADVANCES 2023; 9:eadj6038. [PMID: 38117898 PMCID: PMC10732523 DOI: 10.1126/sciadv.adj6038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/17/2023] [Indexed: 12/22/2023]
Abstract
Advances in the ability to manipulate free-electron phase profiles within the electron microscope have spurred development of quantum-mechanical descriptions of electron energy loss (EEL) processes involving transitions between phase-shaped transverse states. Here, we elucidate an underlying connection between two ostensibly distinct optical polarization analogs identified in EEL experiments as manifestations of the same conserved scattering flux. Our work introduces a procedure for probing general tensorial target characteristics including global mode symmetries and local polarization.
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Affiliation(s)
- Marc R. Bourgeois
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Austin G. Nixon
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | | | - David J. Masiello
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
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10
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Huang S, Duan R, Pramanik N, Go M, Boothroyd C, Liu Z, Wong LJ. Multicolor x-rays from free electron-driven van der Waals heterostructures. SCIENCE ADVANCES 2023; 9:eadj8584. [PMID: 38039369 PMCID: PMC10691772 DOI: 10.1126/sciadv.adj8584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 11/02/2023] [Indexed: 12/03/2023]
Abstract
The emergence of van der Waals (vdW) heterostructures has led to precise and versatile methods of fabricating devices with atomic-scale accuracies. Hence, vdW heterostructures have shown much promise for technologies including photodetectors, photocatalysis, photovoltaic devices, ultrafast photonic devices, and field-effect transistors. These applications, however, remain confined to optical and suboptical regimes. Here, we theoretically show and experimentally demonstrate the use of vdW heterostructures as platforms for multicolor x-ray generation. By driving the vdW heterostructures with free electrons in a table-top setup, we generate x-ray photons whose output spectral profile can be user-customized via the heterostructure design and even controlled in real time. We show that the multicolor photon energies and their corresponding intensities can be tailored by varying the electron energy, the electron beam position, as well as the geometry and composition of the vdW heterostructure. Our results reveal the promise of vdW heterostructures in realizing highly versatile x-ray sources for emerging applications in advanced x-ray imaging and spectroscopy.
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Affiliation(s)
- Sunchao Huang
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Ruihuan Duan
- CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, Nanyang Technological University, 50 Nanyang Avenue, Singapore 637371, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Nikhil Pramanik
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Michael Go
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Chris Boothroyd
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Liang Jie Wong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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11
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Gaida JH, Lourenço-Martins H, Yalunin SV, Feist A, Sivis M, Hohage T, García de Abajo FJ, Ropers C. Lorentz microscopy of optical fields. Nat Commun 2023; 14:6545. [PMID: 37848420 PMCID: PMC10582189 DOI: 10.1038/s41467-023-42054-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 09/25/2023] [Indexed: 10/19/2023] Open
Abstract
In electron microscopy, detailed insights into nanoscale optical properties of materials are gained by spontaneous inelastic scattering leading to electron-energy loss and cathodoluminescence. Stimulated scattering in the presence of external sample excitation allows for mode- and polarization-selective photon-induced near-field electron microscopy (PINEM). This process imprints a spatial phase profile inherited from the optical fields onto the wave function of the probing electrons. Here, we introduce Lorentz-PINEM for the full-field, non-invasive imaging of complex optical near fields at high spatial resolution. We use energy-filtered defocus phase-contrast imaging and iterative phase retrieval to reconstruct the phase distribution of interfering surface-bound modes on a plasmonic nanotip. Our approach is universally applicable to retrieve the spatially varying phase of nanoscale fields and topological modes.
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Affiliation(s)
- John H Gaida
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Hugo Lourenço-Martins
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Sergey V Yalunin
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Armin Feist
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Murat Sivis
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Thorsten Hohage
- Institute of Numerical and Applied Mathematics, University of Göttingen, 37083, Göttingen, Germany
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010, Barcelona, Spain
| | - Claus Ropers
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany.
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany.
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12
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Chen R, Chen J, Gong Z, Zhang X, Zhu X, Yang Y, Kaminer I, Chen H, Zhang B, Lin X. Free-electron Brewster-transition radiation. SCIENCE ADVANCES 2023; 9:eadh8098. [PMID: 37566659 PMCID: PMC10421060 DOI: 10.1126/sciadv.adh8098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 07/12/2023] [Indexed: 08/13/2023]
Abstract
We reveal a mechanism to enhance particle-matter interactions by exploiting the pseudo-Brewster effect of gain materials, presenting an enhancement of at least four orders of magnitude for light emission. This mechanism is enabled by the emergence of an unprecedented phase diagram that maps all phenomena of free-electron transition radiation into three distinct phases in a gain-thickness parameter space, namely, the conventional, intermediate, and Brewster phases, when an electron penetrates a dielectric slab with a modest gain and a finite thickness. Essentially, our revealed mechanism corresponds to the free-electron transition radiation in the Brewster phase, which also features ultrahigh directionality, always at the Brewster angle, regardless of the electron velocity. Counterintuitively, we find that the intensity of this free-electron Brewster-transition radiation is insensitive to the Fabry-Pérot resonance condition and, thus, the variation of slab thickness, and moreover, a weaker gain could lead to a stronger enhancement for light emission.
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Affiliation(s)
- Ruoxi Chen
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
| | - Jialin Chen
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Zheng Gong
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
| | - Xinyan Zhang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
| | - Xingjian Zhu
- School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Yi Yang
- Department of Physics, University of Hong Kong, Hong Kong 999077, China
| | - Ido Kaminer
- Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Hongsheng Chen
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
- Shaoxing Institute of Zhejiang University, Zhejiang University, Shaoxing 312000, China
| | - Baile Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
| | - Xiao Lin
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
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13
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Auad Y, Dias EJC, Tencé M, Blazit JD, Li X, Zagonel LF, Stéphan O, Tizei LHG, García de Abajo FJ, Kociak M. μeV electron spectromicroscopy using free-space light. Nat Commun 2023; 14:4442. [PMID: 37488103 PMCID: PMC10366080 DOI: 10.1038/s41467-023-39979-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 07/03/2023] [Indexed: 07/26/2023] Open
Abstract
The synergy between free electrons and light has recently been leveraged to reach an impressive degree of simultaneous spatial and spectral resolution, enabling applications in microscopy and quantum optics. However, the required combination of electron optics and light injection into the spectrally narrow modes of arbitrary specimens remains a challenge. Here, we demonstrate microelectronvolt spectral resolution with a sub-nanometer probe of photonic modes with quality factors as high as 104. We rely on mode matching of a tightly focused laser beam to whispering gallery modes to achieve a 108-fold increase in light-electron coupling efficiency. By adapting the shape and size of free-space optical beams to address specific physical questions, our approach allows us to interrogate any type of photonic structure with unprecedented spectral and spatial detail.
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Affiliation(s)
- Yves Auad
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels, Barcelona, Spain
| | - Marcel Tencé
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Jean-Denis Blazit
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Xiaoyan Li
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Luiz Fernando Zagonel
- Gleb Wataghin Institute of Physics, University of Campinas - UNICAMP, 13083-859, Campinas, SP, Brazil
| | - Odile Stéphan
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Luiz H G Tizei
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels, Barcelona, Spain.
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010, Barcelona, Spain.
| | - Mathieu Kociak
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France.
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14
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Javier García de Abajo F. Free Electrons for Infrared Nanophotonics. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:643. [PMID: 37613295 DOI: 10.1093/micmic/ozad067.314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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15
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Dias EJC, Madan I, Gargiulo S, Barantani F, Yannai M, Vanacore GM, Kaminer I, Carbone F, García de Abajo FJ. Generation and control of localized terahertz fields in photoemitted electron plasmas. NANOSCALE ADVANCES 2023; 5:3634-3645. [PMID: 37441257 PMCID: PMC10334422 DOI: 10.1039/d3na00168g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/02/2023] [Indexed: 07/15/2023]
Abstract
Dense micron-sized electron plasmas, such as those generated upon irradiation of nanostructured metallic surfaces by intense femtosecond laser pulses, constitute a rich playground to study light-matter interactions, many-body phenomena, and out-of-equilibrium charge dynamics. Besides their fundamental interest, laser-induced plasmas hold great potential for the generation of localized terahertz radiation pulses. However, the underlying mechanisms ruling the formation and evolution of such plasmas are not yet well understood. Here, we develop a comprehensive microscopic theory to predictably describe the spatiotemporal dynamics of laser-pulse-induced plasmas. Through detailed analysis of electron emission, metal screening, and plasma cloud interactions, we investigate the spatial, temporal, and spectral characteristics of the so-generated terahertz fields, which can be extensively controlled through the metal morphology and the illumination conditions. We further describe the interaction with femtosecond electron beams to explain recent ultrafast electron microscopy experiments, whereby the position and temporal dependence of the observed electron acceleration permits assessing the associated terahertz field. Besides its potential application to the design of low-frequency light sources, our work contributes fundamental insight into the generation and dynamics of micron-scale electron plasmas and their interaction with ultrafast electron pulses.
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Affiliation(s)
- Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology 08860 Castelldefels Barcelona Spain
| | - Ivan Madan
- Institute of Physics, École Polytechnique Fédérale de Lausanne Lausanne 1015 Switzerland
| | - Simone Gargiulo
- Institute of Physics, École Polytechnique Fédérale de Lausanne Lausanne 1015 Switzerland
| | - Francesco Barantani
- Institute of Physics, École Polytechnique Fédérale de Lausanne Lausanne 1015 Switzerland
- Department of Quantum Matter Physics, University of Geneva 24 Quai Ernest-Ansermet Geneva 1211 Switzerland
| | - Michael Yannai
- Technion - Israel Institute of Technology Haifa 3200003 Israel
| | - Giovanni Maria Vanacore
- Department of Materials Science, University of Milano-Bicocca Via Cozzi, 55 Milano 20126 Italy
| | - Ido Kaminer
- Technion - Israel Institute of Technology Haifa 3200003 Israel
| | - Fabrizio Carbone
- Institute of Physics, École Polytechnique Fédérale de Lausanne Lausanne 1015 Switzerland
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology 08860 Castelldefels Barcelona Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats Passeig Lluís Companys 23 08010 Barcelona Spain
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16
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García de Abajo FJ, Ropers C. Spatiotemporal Electron Beam Focusing through Parallel Interactions with Shaped Optical Fields. PHYSICAL REVIEW LETTERS 2023; 130:246901. [PMID: 37390412 DOI: 10.1103/physrevlett.130.246901] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 05/17/2023] [Indexed: 07/02/2023]
Abstract
The ability to modulate free electrons with light has emerged as a powerful tool to produce attosecond electron wave packets. However, research has so far aimed at the manipulation of the longitudinal wave function component, while the transverse degrees of freedom have primarily been utilized for spatial rather than temporal shaping. Here, we show that the coherent superposition of parallel light-electron interactions in transversally separate zones allows for a simultaneous spatial and temporal compression of a convergent electron wave function, enabling the formation of sub-Ångström focal spots of attosecond duration. Specifically, spots spanning just ∼3% of the light optical cycle are shown to be formed, accompanied by an increase by only a factor of 2 in spatial extension relative to an unperturbed beam. The proposed approach will facilitate the exploration of previously inaccessible ultrafast atomic-scale phenomena, in particular enabling attosecond scanning transmission electron microscopy.
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Affiliation(s)
- F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Claus Ropers
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
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17
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Shi X, Kurman Y, Shentcis M, Wong LJ, García de Abajo FJ, Kaminer I. Free-electron interactions with van der Waals heterostructures: a source of focused X-ray radiation. LIGHT, SCIENCE & APPLICATIONS 2023; 12:148. [PMID: 37321995 DOI: 10.1038/s41377-023-01141-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 03/06/2023] [Accepted: 03/30/2023] [Indexed: 06/17/2023]
Abstract
The science and technology of X-ray optics have come far, enabling the focusing of X-rays for applications in high-resolution X-ray spectroscopy, imaging, and irradiation. In spite of this, many forms of tailoring waves that had substantial impact on applications in the optical regime have remained out of reach in the X-ray regime. This disparity fundamentally arises from the tendency of refractive indices of all materials to approach unity at high frequencies, making X-ray-optical components such as lenses and mirrors much harder to create and often less efficient. Here, we propose a new concept for X-ray focusing based on inducing a curved wavefront into the X-ray generation process, resulting in the intrinsic focusing of X-ray waves. This concept can be seen as effectively integrating the optics to be part of the emission mechanism, thus bypassing the efficiency limits imposed by X-ray optical components, enabling the creation of nanobeams with nanoscale focal spot sizes and micrometer-scale focal lengths. Specifically, we implement this concept by designing aperiodic vdW heterostructures that shape X-rays when driven by free electrons. The parameters of the focused hotspot, such as lateral size and focal depth, are tunable as a function of an interlayer spacing chirp and electron energy. Looking forward, ongoing advances in the creation of many-layer vdW heterostructures open unprecedented horizons of focusing and arbitrary shaping of X-ray nanobeams.
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Affiliation(s)
- Xihang Shi
- Solid State Institute and Faculty of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Yaniv Kurman
- Solid State Institute and Faculty of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Michael Shentcis
- Solid State Institute and Faculty of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Liang Jie Wong
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Ido Kaminer
- Solid State Institute and Faculty of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel.
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18
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Karnieli A, Fan S. Jaynes-Cummings interaction between low-energy free electrons and cavity photons. SCIENCE ADVANCES 2023; 9:eadh2425. [PMID: 37256955 PMCID: PMC10413651 DOI: 10.1126/sciadv.adh2425] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/21/2023] [Indexed: 06/02/2023]
Abstract
The Jaynes-Cummings Hamiltonian is at the core of cavity quantum electrodynamics; however, it relies on bound-electron emitters fundamentally limited by the binding Coulomb potential. In this work, we propose theoretically a new approach to realizing the Jaynes-Cummings model using low-energy free electrons coupled to dielectric microcavities and exemplify several quantum technologies made possible by this approach. Using quantum recoil, a large detuning inhibits the emission of multiple consecutive photons, effectively transforming the free electron into a few-level system coupled to the cavity mode. We show that this approach can be used for generation of single photons, photon pairs, and even a quantum SWAP gate between a photon and a free electron, with unity efficiency and high fidelity. Tunable by their kinetic energy, quantum free electrons are inherently versatile emitters with an engineerable emission wavelength. Hence, they pave the way toward new possibilities for quantum interconnects between photonic platforms at disparate spectral regimes.
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Affiliation(s)
- Aviv Karnieli
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv, Israel
| | - Shanhui Fan
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
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19
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Lim J, Kumar S, Ang YS, Ang LK, Wong LJ. Quantum Interference between Fundamentally Different Processes Is Enabled by Shaped Input Wavefunctions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205750. [PMID: 36737853 PMCID: PMC10074114 DOI: 10.1002/advs.202205750] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/06/2022] [Indexed: 06/18/2023]
Abstract
This work presents a general framework for quantum interference between processes that can involve different fundamental particles or quasi-particles. This framework shows that shaping input wavefunctions is a versatile and powerful tool for producing and controlling quantum interference between distinguishable pathways, beyond previously explored quantum interference between indistinguishable pathways. Two examples of quantum interference enabled by shaping in interactions between free electrons, bound electrons, and photons are presented: i) the vanishing of the zero-loss peak by destructive quantum interference when a shaped electron wavepacket couples to light, under conditions where the electron's zero-loss peak otherwise dominates; ii) quantum interference between free electron and atomic (bound electron) spontaneous emission processes, which can be significant even when the free electron and atom are far apart, breaking the common notion that a free electron and an atom must be close by to significantly affect each other's processes. Conclusions show that emerging quantum wave-shaping techniques unlock the door to greater versatility in light-matter interactions and other quantum processes in general.
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Affiliation(s)
- Jeremy Lim
- Science, Mathematics and TechnologySingapore University of Technology and Design8 Somapah RoadSingapore487372Singapore
| | - Suraj Kumar
- School of Electrical and Electronic EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
| | - Yee Sin Ang
- Science, Mathematics and TechnologySingapore University of Technology and Design8 Somapah RoadSingapore487372Singapore
| | - Lay Kee Ang
- Science, Mathematics and TechnologySingapore University of Technology and Design8 Somapah RoadSingapore487372Singapore
| | - Liang Jie Wong
- School of Electrical and Electronic EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
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20
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Yannai M, Dahan R, Gorlach A, Adiv Y, Wang K, Madan I, Gargiulo S, Barantani F, Dias EJC, Vanacore GM, Rivera N, Carbone F, García de Abajo FJ, Kaminer I. Ultrafast Electron Microscopy of Nanoscale Charge Dynamics in Semiconductors. ACS NANO 2023; 17:3645-3656. [PMID: 36736033 DOI: 10.1021/acsnano.2c10481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The ultrafast dynamics of charge carriers in solids plays a pivotal role in emerging optoelectronics, photonics, energy harvesting, and quantum technology applications. However, the investigation and direct visualization of such nonequilibrium phenomena remains as a long-standing challenge, owing to the nanometer-femtosecond spatiotemporal scales at which the charge carriers evolve. Here, we propose and demonstrate an interaction mechanism enabling nanoscale imaging of the femtosecond dynamics of charge carriers in solids. This imaging modality, which we name charge dynamics electron microscopy (CDEM), exploits the strong interaction of free-electron pulses with terahertz (THz) near fields produced by the moving charges in an ultrafast scanning transmission electron microscope. The measured free-electron energy at different spatiotemporal coordinates allows us to directly retrieve the THz near-field amplitude and phase, from which we reconstruct movies of the generated charges by comparison to microscopic theory. The CDEM technique thus allows us to investigate previously inaccessible spatiotemporal regimes of charge dynamics in solids, providing insight into the photo-Dember effect and showing oscillations of photogenerated electron-hole distributions inside a semiconductor. Our work facilitates the exploration of a wide range of previously inaccessible charge-transport phenomena in condensed matter using ultrafast electron microscopy.
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Affiliation(s)
- Michael Yannai
- Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Raphael Dahan
- Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Alexey Gorlach
- Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Yuval Adiv
- Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Kangpeng Wang
- Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Ivan Madan
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 6, Lausanne 1015, Switzerland
| | - Simone Gargiulo
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 6, Lausanne 1015, Switzerland
| | - Francesco Barantani
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 6, Lausanne 1015, Switzerland
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Giovanni Maria Vanacore
- Department of Materials Science, University of Milano-Bicocca, Via Cozzi 55, 20121 Milano, Italy
| | - Nicholas Rivera
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Fabrizio Carbone
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Station 6, Lausanne 1015, Switzerland
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Ido Kaminer
- Technion - Israel Institute of Technology, Haifa 3200003, Israel
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21
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Madan I, Dias EJC, Gargiulo S, Barantani F, Yannai M, Berruto G, LaGrange T, Piazza L, Lummen TTA, Dahan R, Kaminer I, Vanacore GM, García de Abajo FJ, Carbone F. Charge Dynamics Electron Microscopy: Nanoscale Imaging of Femtosecond Plasma Dynamics. ACS NANO 2023; 17:3657-3665. [PMID: 36780289 PMCID: PMC9979644 DOI: 10.1021/acsnano.2c10482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Understanding and actively controlling the spatiotemporal dynamics of nonequilibrium electron clouds is fundamental for the design of light and electron sources, high-power electronic devices, and plasma-based applications. However, electron clouds evolve in a complex collective fashion on the nanometer and femtosecond scales, producing electromagnetic screening that renders them inaccessible to existing optical probes. Here, we solve the long-standing challenge of characterizing the evolution of electron clouds generated upon irradiation of metallic structures using an ultrafast transmission electron microscope to record the charged plasma dynamics. Our approach to charge dynamics electron microscopy (CDEM) is based on the simultaneous detection of electron-beam acceleration and broadening with nanometer/femtosecond resolution. By combining experimental results with comprehensive microscopic theory, we provide a deep understanding of this highly out-of-equilibrium regime, including previously inaccessible intricate microscopic mechanisms of electron emission, screening by the metal, and collective cloud dynamics. Beyond the present specific demonstration, the here-introduced CDEM technique grants us access to a wide range of nonequilibrium electrodynamic phenomena involving the ultrafast evolution of bound and free charges on the nanoscale.
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Affiliation(s)
- Ivan Madan
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
| | - Eduardo J. C. Dias
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona08860, Spain
| | - Simone Gargiulo
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
| | - Francesco Barantani
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
- Department
of Quantum Matter Physics, University of
Geneva, Geneva1211, Switzerland
| | - Michael Yannai
- Department
of Electrical and Computer Engineering, Technion Israel Institute of Technology, Haifa32000, Israel
| | - Gabriele Berruto
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
| | - Thomas LaGrange
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
| | - Luca Piazza
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
| | | | - Raphael Dahan
- Department
of Electrical and Computer Engineering, Technion Israel Institute of Technology, Haifa32000, Israel
| | - Ido Kaminer
- Department
of Electrical and Computer Engineering, Technion Israel Institute of Technology, Haifa32000, Israel
| | - Giovanni Maria Vanacore
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
- Department
of Materials Science, University of Milano-Bicocca, Milano20126, Italy
| | - F. Javier García de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona08860, Spain
- ICREA, Institució
Catalana de Recerca i Estudis Avançats, Barcelona08010, Spain
| | - Fabrizio Carbone
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne1015, Switzerland
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22
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Arregui G, Ng RC, Albrechtsen M, Stobbe S, Sotomayor-Torres CM, García PD. Cavity Optomechanics with Anderson-Localized Optical Modes. PHYSICAL REVIEW LETTERS 2023; 130:043802. [PMID: 36763436 DOI: 10.1103/physrevlett.130.043802] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 12/16/2022] [Indexed: 06/18/2023]
Abstract
Confining photons in cavities enhances the interaction between light and matter. In cavity optomechanics, this enables a wealth of phenomena ranging from optomechanically induced transparency to macroscopic objects cooled to their motional ground state. Previous work in cavity optomechanics employed devices where ubiquitous structural disorder played no role beyond perturbing resonance frequencies and quality factors. More generally, the interplay between disorder, which must be described by statistical physics, and optomechanical effects has thus far been unexplored. Here, we demonstrate how sidewall roughness in air-slot photonic-crystal waveguides can induce sufficiently strong backscattering of slot-guided light to create Anderson-localized modes with quality factors as high as half a million and mode volumes estimated to be below the diffraction limit. We observe how the interaction between these disorder-induced optical modes and in-plane mechanical modes of the slotted membrane is governed by a distribution of coupling rates, which can exceed g_{o}/2π∼200 kHz, leading to mechanical amplification up to self sustained oscillations via optomechanical backaction. Our Letter constitutes the first steps towards understanding optomechanics in the multiple-scattering regime and opens new perspectives for exploring complex systems with a multitude of mutually coupled degrees of freedom.
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Affiliation(s)
- G Arregui
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, Kgs. Lyngby, DK-2800, Denmark
| | - R C Ng
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - M Albrechtsen
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, Kgs. Lyngby, DK-2800, Denmark
| | - S Stobbe
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, Kgs. Lyngby, DK-2800, Denmark
| | - C M Sotomayor-Torres
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - P D García
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
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23
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Karnieli A, Tsesses S, Yu R, Rivera N, Zhao Z, Arie A, Fan S, Kaminer I. Quantum sensing of strongly coupled light-matter systems using free electrons. SCIENCE ADVANCES 2023; 9:eadd2349. [PMID: 36598994 PMCID: PMC9812396 DOI: 10.1126/sciadv.add2349] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Strong coupling in light-matter systems is a central concept in cavity quantum electrodynamics and is essential for many quantum technologies. Especially in the optical range, full control of highly connected multi-qubit systems necessitates quantum coherent probes with nanometric spatial resolution, which are currently inaccessible. Here, we propose the use of free electrons as high-resolution quantum sensors for strongly coupled light-matter systems. Shaping the free-electron wave packet enables the measurement of the quantum state of the entire hybrid systems. We specifically show how quantum interference of the free-electron wave packet gives rise to a quantum-enhanced sensing protocol for the position and dipole orientation of a subnanometer emitter inside a cavity. Our results showcase the great versatility and applicability of quantum interactions between free electrons and strongly coupled cavities, relying on the unique properties of free electrons as strongly interacting flying qubits with miniscule dimensions.
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Affiliation(s)
- Aviv Karnieli
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv 69978 Tel Aviv, Israel
| | - Shai Tsesses
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - Renwen Yu
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Nicholas Rivera
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Zhexin Zhao
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Ady Arie
- School of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Shanhui Fan
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Ido Kaminer
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion–Israel Institute of Technology, Haifa 32000, Israel
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24
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Konečná A, Iyikanat F, García de Abajo FJ. Entangling free electrons and optical excitations. SCIENCE ADVANCES 2022; 8:eabo7853. [PMID: 36427323 PMCID: PMC9699672 DOI: 10.1126/sciadv.abo7853] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 10/07/2022] [Indexed: 05/30/2023]
Abstract
The inelastic interaction between flying particles and optical nanocavities gives rise to entangled states in which some excitations of the latter are paired with momentum changes in the former. Specifically, free-electron entanglement with nanocavity modes opens appealing opportunities associated with the strong interaction capabilities of the electrons. However, the achievable degree of entanglement is currently limited by the lack of control over the resulting state mixtures. Here, we propose a scheme to generate pure entanglement between designated optical-cavity excitations and separable free-electron states. We shape the electron wave function profile to select the accessible cavity modes and simultaneously associate them with targeted electron scattering directions. This concept is exemplified through theoretical calculations of free-electron entanglement with degenerate and nondegenerate plasmon modes in silver nanoparticles and atomic vibrations in an inorganic molecule. The generated entanglement can be further propagated through its electron component to extend quantum interactions beyond existing protocols.
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Affiliation(s)
- Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- Central European Institute of Technology, Brno University of Technology, Brno 61200, Czech Republic
| | - Fadil Iyikanat
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - F. Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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25
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Yang H, Konečná A, Xu X, Cheong SW, Batson PE, García de Abajo FJ, Garfunkel E. Simultaneous Imaging of Dopants and Free Charge Carriers by Monochromated EELS. ACS NANO 2022; 16:18795-18805. [PMID: 36317944 DOI: 10.1021/acsnano.2c07540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Doping inhomogeneities in solids are not uncommon, but their microscopic observation and understanding are limited due to the lack of bulk-sensitive experimental techniques with high enough spatial and spectral resolution. Here, we demonstrate nanoscale imaging of both dopants and free charge carriers in La-doped BaSnO3 (BLSO) using high-resolution electron energy-loss spectroscopy (EELS). By analyzing high- and low-energy excitations in EELS, we reveal chemical and electronic inhomogeneities within a single BLSO nanocrystal. The inhomogeneous doping leads to distinctive localized infrared surface plasmons, including a previously unobserved plasmon mode that is highly confined between high- and low-doping regions. We further quantify the carrier density, effective mass, and dopant activation percentage by EELS and transport measurements on the bulk single crystals of BLSO. These results not only represent a practical approach for studying heterogeneities in solids and understanding structure-property relationships at the nanoscale, but also demonstrate the possibility of infrared plasmon tuning by leveraging nanoscale doping texture.
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Affiliation(s)
- Hongbin Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey08854, United States
| | - Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
- Central European Institute of Technology, Brno University of Technology, 61200Brno, Czech Republic
| | - Xianghan Xu
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
| | - Philip E Batson
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010Barcelona, Spain
| | - Eric Garfunkel
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey08854, United States
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
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26
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Akbari K, Di Giulio V, García de Abajo FJ. Optical manipulation of matter waves. SCIENCE ADVANCES 2022; 8:eabq2659. [PMID: 36260664 DOI: 10.1126/sciadv.abq2659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Light is used to steer the motion of atoms in free space, enabling cooling and trapping of matter waves through ponderomotive forces and Doppler-mediated photon scattering. Likewise, light interaction with free electrons has recently emerged as a versatile approach to modulate the electron wave function for applications in ultrafast electron microscopy. Here, we combine these two worlds, theoretically demonstrating that matter waves can be optically manipulated via inelastic interactions with optical fields. This allows us to modulate the translational part of the wave function and produce temporally and spatially compressed atomic beam pulses. We realize such modulation through stimulated photon absorption and emission by atoms traversing phase-matching evanescent optical fields generated upon light scattering by a nanostructure and via stimulated Compton scattering in free space without any assistance from material media. Our results support optical manipulation of matter waves as a powerful tool for microscopy, spectroscopy, and exploration of fundamental phenomena associated with light-atom interactions.
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Affiliation(s)
- Kamran Akbari
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Valerio Di Giulio
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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27
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Madan I, Leccese V, Mazur A, Barantani F, LaGrange T, Sapozhnik A, Tengdin PM, Gargiulo S, Rotunno E, Olaya JC, Kaminer I, Grillo V, de Abajo FJG, Carbone F, Vanacore GM. Ultrafast Transverse Modulation of Free Electrons by Interaction with Shaped Optical Fields. ACS PHOTONICS 2022; 9:3215-3224. [PMID: 36281329 PMCID: PMC9585634 DOI: 10.1021/acsphotonics.2c00850] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Indexed: 05/13/2023]
Abstract
Spatiotemporal electron-beam shaping is a bold frontier of electron microscopy. Over the past decade, shaping methods evolved from static phase plates to low-speed electrostatic and magnetostatic displays. Recently, a swift change of paradigm utilizing light to control free electrons has emerged. Here, we experimentally demonstrate arbitrary transverse modulation of electron beams without complicated electron-optics elements or material nanostructures, but rather using shaped light beams. On-demand spatial modulation of electron wavepackets is obtained via inelastic interaction with transversely shaped ultrafast light fields controlled by an external spatial light modulator. We illustrate this method for the cases of Hermite-Gaussian and Laguerre-Gaussian modulation and discuss their use in enhancing microscope sensitivity. Our approach dramatically widens the range of patterns that can be imprinted on the electron profile and greatly facilitates tailored electron-beam shaping.
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Affiliation(s)
- Ivan Madan
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Veronica Leccese
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Adam Mazur
- HOLOEYE
Photonics AG, Volmerstrasse 1, 12489 Berlin, Germany
| | - Francesco Barantani
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
- Department
of Quantum Matter Physics, University of
Geneva, 1211 Geneva, Switzerland
| | - Thomas LaGrange
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Alexey Sapozhnik
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Phoebe M. Tengdin
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Simone Gargiulo
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Enzo Rotunno
- Centro
S3, Istituto di Nanoscienze-CNR, 41125 Modena, Italy
| | | | - Ido Kaminer
- Department
of Electrical and Computer Engineering, Technion, Haifa 32000, Israel
| | | | - F. Javier García de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Fabrizio Carbone
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne, Lausanne, 1015, Switzerland
| | - Giovanni Maria Vanacore
- Department
of Materials Science, University of Milano-Bicocca, Via Cozzi 55, 20126 Milano, Italy
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28
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Recent Advances in Smart Hydrogels Prepared by Ionizing Radiation Technology for Biomedical Applications. Polymers (Basel) 2022; 14:polym14204377. [PMID: 36297955 PMCID: PMC9608571 DOI: 10.3390/polym14204377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/27/2022] [Accepted: 10/12/2022] [Indexed: 11/23/2022] Open
Abstract
Materials with excellent biocompatibility and targeting can be widely used in the biomedical field. Hydrogels are an excellent biomedical material, which are similar to living tissue and cannot affect the metabolic process of living organisms. Moreover, the three-dimensional network structure of hydrogel is conducive to the storage and slow release of drugs. Compared to the traditional hydrogel preparation technologies, ionizing radiation technology has high efficiency, is green, and has environmental protection. This technology can easily adjust mechanical properties, swelling, and so on. This review provides a classification of hydrogels and different preparation methods and highlights the advantages of ionizing radiation technology in smart hydrogels used for biomedical applications.
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29
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Bourgeois MR, Nixon AG, Chalifour M, Beutler EK, Masiello DJ. Polarization-Resolved Electron Energy Gain Nanospectroscopy With Phase-Structured Electron Beams. NANO LETTERS 2022; 22:7158-7165. [PMID: 36036765 DOI: 10.1021/acs.nanolett.2c02375] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Free-electron-based measurements in scanning transmission electron microscopes (STEMs) reveal valuable information on the broadband spectral responses of nanoscale systems with deeply subdiffraction limited spatial resolution. Leveraging recent advances in manipulating the spatial phase profile of the transverse electron wavefront, we theoretically describe interactions between the electron probe and optically stimulated nanophotonic targets in which the probe gains energy while simultaneously transitioning between transverse states with distinct phase profiles. Exploiting the selection rules governing such transitions, we propose phase-shaped electron energy gain nanospectroscopy for probing the 3D polarization-resolved response field of an optically excited target with nanoscale spatial resolution. Considering ongoing instrumental developments, polarized generalizations of STEM electron energy loss and gain measurements hold the potential to become powerful tools for fundamental studies of quantum materials and their interaction with nearby nanostructures supporting localized surface plasmon or phonon polaritons as well as for noninvasive imaging and nanoscale 3D field tomography.
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Affiliation(s)
- Marc R Bourgeois
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Austin G Nixon
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Matthieu Chalifour
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Elliot K Beutler
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - David J Masiello
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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30
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García de Abajo FJ, Dias EJC, Di Giulio V. Complete Excitation of Discrete Quantum Systems by Single Free Electrons. PHYSICAL REVIEW LETTERS 2022; 129:093401. [PMID: 36083663 DOI: 10.1103/physrevlett.129.093401] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
We reveal a wealth of nonlinear and recoil effects in the interaction between individual low-energy electrons (≲100 eV) and samples comprising a discrete number of states. Adopting a quantum theoretical description of combined free-electron and two-level systems, we find a maximum achievable excitation probability of 100%, which requires specific conditions relating to the coupling strength and the transition symmetry, as we illustrate through calculations for dipolar and quadrupolar modes. Strong recoil effects are observed when the kinetic energy of the probe lies close to the transition threshold, although the associated probability remains independent of the electron wave function even when fully accounting for nonlinear interactions with arbitrarily complex multilevel samples. Our work reveals the potential of free electrons to control localized excitations and delineates the boundaries of such control.
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Affiliation(s)
- F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Valerio Di Giulio
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
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31
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Feist A, Huang G, Arend G, Yang Y, Henke JW, Raja AS, Kappert FJ, Wang RN, Lourenço-Martins H, Qiu Z, Liu J, Kfir O, Kippenberg TJ, Ropers C. Cavity-mediated electron-photon pairs. Science 2022; 377:777-780. [PMID: 35951690 DOI: 10.1126/science.abo5037] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Quantum information, communication, and sensing rely on the generation and control of quantum correlations in complementary degrees of freedom. Free electrons coupled to photonics promise novel hybrid quantum technologies, although single-particle correlations and entanglement have yet to be shown. In this work, we demonstrate the preparation of electron-photon pair states using the phase-matched interaction of free electrons with the evanescent vacuum field of a photonic chip-based optical microresonator. Spontaneous inelastic scattering produces intracavity photons coincident with energy-shifted electrons, which we employ for noise-suppressed optical mode imaging. This parametric pair-state preparation will underpin the future development of free-electron quantum optics, providing a route to quantum-enhanced imaging, electron-photon entanglement, and heralded single-electron and Fock-state photon sources.
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Affiliation(s)
- Armin Feist
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
| | - Guanhao Huang
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Germaine Arend
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
| | - Yujia Yang
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jan-Wilke Henke
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
| | - Arslan Sajid Raja
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - F Jasmin Kappert
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
| | - Rui Ning Wang
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Hugo Lourenço-Martins
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
| | - Zheru Qiu
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Junqiu Liu
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ofer Kfir
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
| | - Tobias J Kippenberg
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,Center for Quantum Science and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Claus Ropers
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany.,4th Physical Institute - Solids and Nanostructures, University of Göttingen, D-37077 Göttingen, Germany
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32
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Karnieli A, Roitman D, Liebtrau M, Tsesses S, Van Nielen N, Kaminer I, Arie A, Polman A. Cylindrical Metalens for Generation and Focusing of Free-Electron Radiation. NANO LETTERS 2022; 22:5641-5650. [PMID: 35791573 PMCID: PMC9335868 DOI: 10.1021/acs.nanolett.1c04556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Metasurfaces constitute a powerful approach to generate and control light by engineering optical material properties at the subwavelength scale. Recently, this concept was applied to manipulate free-electron radiation phenomena, rendering versatile light sources with unique functionalities. In this Letter, we experimentally demonstrate spectral and angular control over coherent light emission by metasurfaces that interact with free-electrons under grazing incidence. Specifically, we study metalenses based on chirped metagratings that simultaneously emit and shape Smith-Purcell radiation in the visible and near-infrared spectral regime. In good agreement with theory, we observe the far-field signatures of strongly convergent and divergent cylindrical radiation wavefronts using in situ hyperspectral angle-resolved light detection in a scanning electron microscope. Furthermore, we theoretically explore simultaneous control over the polarization and wavefront of Smith-Purcell radiation via a split-ring-resonator metasurface, enabling tunable operation by spatially selective mode excitation at nanometer resolution. Our work highlights the potential of merging metasurfaces with free-electron excitations for versatile and highly tunable radiation sources in wide-ranging spectral regimes.
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Affiliation(s)
- Aviv Karnieli
- Raymond
and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dolev Roitman
- Raymond
and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Matthias Liebtrau
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Shai Tsesses
- Andrew
and Erna Viterbi Department of Electrical Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Nika Van Nielen
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Ido Kaminer
- Andrew
and Erna Viterbi Department of Electrical Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Ady Arie
- School
of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Albert Polman
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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33
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Dieperink M, Scalerandi F, Albrecht W. Correlating structure, morphology and properties of metal nanostructures by combining single-particle optical spectroscopy and electron microscopy. NANOSCALE 2022; 14:7460-7472. [PMID: 35481561 DOI: 10.1039/d1nr08130f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The nanoscale morphology of metal nanostructures directly defines their optical, catalytic and electronic properties and even small morphological changes can cause significant property variations. On the one hand, this dependence allows for precisely tuning and exploring properties by shape engineering; next to advanced synthesis protocols, post-synthesis modification through tailored laser modification has become an emerging tool to do so. On the other hand, with this interconnection also comes the quest for detailed structure-property correlation and understanding of laser-induced reshaping processes on the individual nanostructure level beyond ensemble averages. With the development of single-particle (ultrafast) optical spectroscopy techniques and advanced electron microscopy such understanding can in principle be gained at the femtosecond temporal and atomic spatial scale, respectively. However, accessing both on the same individual nanostructure is far from straightforward as it requires the combination of optical spectroscopy and electron microscopy. In this Minireview, we highlight key studies from recent years that performed such correlative measurements on the same individual metal nanostructure either in a consecutive ex situ manner or in situ inside the electron microscope. We demonstrate that such a detailed correlation is critical for revealing the full picture of the structure-property relationship and the physics behind light-induced nanostructure modifications. We put emphasis on the advantages and disadvantages of each methodology as well as on the unique information that one can gain only by correlative studies performed on the same individual nanostructure and end with an outlook on possible further development of this field in the near future.
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Affiliation(s)
- Mees Dieperink
- Department of Sustainable Energy Materials, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
| | - Francesca Scalerandi
- Department of Sustainable Energy Materials, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
| | - Wiebke Albrecht
- Department of Sustainable Energy Materials, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
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34
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Huang S, Duan R, Pramanik N, Boothroyd C, Liu Z, Wong LJ. Enhanced Versatility of Table-Top X-Rays from Van der Waals Structures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105401. [PMID: 35355443 PMCID: PMC9165495 DOI: 10.1002/advs.202105401] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Van der Waals (vdW) materials have attracted much interest for their myriad unique electronic, mechanical, and thermal properties. In particular, they are promising candidates for monochromatic, table-top X-ray sources. This work reveals that the versatility of the table-top vdW X-ray source goes beyond what has been demonstrated so far. By introducing a tilt angle between the vdW structure and the incident electron beam, it is theoretically and experimentally shown that the accessible photon energy range is more than doubled. This allows for greater versatility in real-time tuning of the vdW X-ray source. Furthermore, this work shows that the accessible photon energy range is maximized by simultaneously controlling both the electron energy and the vdW structure tilt. These results will pave the way for highly tunable, compact X-ray sources, with potential applications including hyperspectral X-ray fluoroscopy and X-ray quantum optics.
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Affiliation(s)
- Sunchao Huang
- School of Electrical and Electronic EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
| | - Ruihuan Duan
- CINTRA CNRS/NTU/THALESUMI 3288Research Techno PlazaNanyang Technological University50 Nanyang AvenueSingapore637371Singapore
| | - Nikhil Pramanik
- School of Electrical and Electronic EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
| | - Chris Boothroyd
- School of Materials Science and EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
- Facility for AnalysisCharacterisationTesting, and Simulation (FACTS)Nanyang Technological University50 Nanyang AvenueSingapore639798Singapore
| | - Zheng Liu
- School of Materials Science and EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
| | - Liang Jie Wong
- School of Electrical and Electronic EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
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35
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Fiedler S, Stamatopoulou PE, Assadillayev A, Wolff C, Sugimoto H, Fujii M, Mortensen NA, Raza S, Tserkezis C. Disentangling Cathodoluminescence Spectra in Nanophotonics: Particle Eigenmodes vs Transition Radiation. NANO LETTERS 2022; 22:2320-2327. [PMID: 35286099 DOI: 10.1021/acs.nanolett.1c04754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cathodoluminescence spectroscopy performed in an electron microscope has proven a versatile tool for analyzing the near- and far-field optical response of plasmonic and dielectric nanostructures. Nevertheless, the transition radiation produced by electron impact is often disregarded in the interpretation of the spectra recorded from resonant nanoparticles. Here we show, experimentally and theoretically, that transition radiation can by itself generate distinct resonances that, depending on the time-of-flight of the electron beam inside the particle, can result from constructive or destructive interference in time. Superimposed on the eigenmodes of the investigated structures, these resonances can distort the recorded spectrum and lead to potentially erroneous assignment of modal characters to the spectral features. We develop an intuitive analogy that helps distinguish between the two contributions. As an example, we focus on the case of silicon nanospheres and show that our analysis facilitates the unambiguous interpretation of experimental measurements on Mie-resonant nanoparticles.
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Affiliation(s)
- Saskia Fiedler
- Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - P Elli Stamatopoulou
- Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Artyom Assadillayev
- Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
- Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kongens Lyngby, Denmark
| | - Christian Wolff
- Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Hiroshi Sugimoto
- Department of Electrical and Electronic Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan
| | - Minoru Fujii
- Department of Electrical and Electronic Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan
| | - N Asger Mortensen
- Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
- Danish Institute for Advanced Study, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Søren Raza
- Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kongens Lyngby, Denmark
| | - Christos Tserkezis
- Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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36
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Brokkelkamp A, Ter Hoeve J, Postmes I, van Heijst SE, Maduro L, Davydov AV, Krylyuk S, Rojo J, Conesa-Boj S. Spatially Resolved Band Gap and Dielectric Function in Two-Dimensional Materials from Electron Energy Loss Spectroscopy. J Phys Chem A 2022; 126:1255-1262. [PMID: 35167301 PMCID: PMC8883475 DOI: 10.1021/acs.jpca.1c09566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The electronic properties of two-dimensional (2D) materials depend sensitively on the underlying atomic arrangement down to the monolayer level. Here we present a novel strategy for the determination of the band gap and complex dielectric function in 2D materials achieving a spatial resolution down to a few nanometers. This approach is based on machine learning techniques developed in particle physics and makes possible the automated processing and interpretation of spectral images from electron energy loss spectroscopy (EELS). Individual spectra are classified as a function of the thickness with K-means clustering, and then used to train a deep-learning model of the zero-loss peak background. As a proof of concept we assess the band gap and dielectric function of InSe flakes and polytypic WS2 nanoflowers and correlate these electrical properties with the local thickness. Our flexible approach is generalizable to other nanostructured materials and to higher-dimensional spectroscopies and is made available as a new release of the open-source EELSfitter framework.
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Affiliation(s)
- Abel Brokkelkamp
- Kavli Institute of Nanoscience, Delft University of Technology, 2628CJ Delft, The Netherlands
| | - Jaco Ter Hoeve
- Nikhef Theory Group, Science Park 105, 1098 XG Amsterdam, The Netherlands.,Physics and Astronomy, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Isabel Postmes
- Kavli Institute of Nanoscience, Delft University of Technology, 2628CJ Delft, The Netherlands
| | - Sabrya E van Heijst
- Kavli Institute of Nanoscience, Delft University of Technology, 2628CJ Delft, The Netherlands
| | - Louis Maduro
- Kavli Institute of Nanoscience, Delft University of Technology, 2628CJ Delft, The Netherlands
| | - Albert V Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sergiy Krylyuk
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Juan Rojo
- Nikhef Theory Group, Science Park 105, 1098 XG Amsterdam, The Netherlands.,Physics and Astronomy, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Sonia Conesa-Boj
- Kavli Institute of Nanoscience, Delft University of Technology, 2628CJ Delft, The Netherlands
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37
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Yu R, Konečná A, de Abajo FJG. Inelastic Scattering of Electron Beams by Nonreciprocal Nanotructures. PHYSICAL REVIEW LETTERS 2021; 127:157404. [PMID: 34678034 DOI: 10.1103/physrevlett.127.157404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Probing optical excitations with high resolution is important for understanding their dynamics and controlling their interaction with other photonic elements. This can be done using state-of-the-art electron microscopes, which provide the means to sample optical excitations with combined meV-sub-nm energy-space resolution. For reciprocal photonic systems, electrons traveling in opposite directions produce identical signals, while this symmetry is broken in nonreciprocal structures. Here, we theoretically investigate this phenomenon by analyzing electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) for structures consisting of magnetically biased InAs as an instance of gyrotropic nonreciprocal material. We find that the spectral features associated with excitations of InAs films depend on the electron propagation direction in both EELS and CL, and can be tuned by varying the applied magnetic field within a relatively modest subtesla regime. The magnetic field modifies the optical field distribution of the sampled resonances, and this in turn produces a direction-dependent coupling to the electron. The present results pave the way to the use of electron microscope spectroscopies to explore the near-field characteristics of nonreciprocal systems with high spatial resolution.
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Affiliation(s)
- Renwen Yu
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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38
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Dahan R, Gorlach A, Haeusler U, Karnieli A, Eyal O, Yousefi P, Segev M, Arie A, Eisenstein G, Hommelhoff P, Kaminer I. Imprinting the quantum statistics of photons on free electrons. Science 2021; 373:eabj7128. [PMID: 34446445 DOI: 10.1126/science.abj7128] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Raphael Dahan
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Alexey Gorlach
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Urs Haeusler
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstraße 1, Erlangen 91058, Germany
| | - Aviv Karnieli
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ori Eyal
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Peyman Yousefi
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstraße 1, Erlangen 91058, Germany
| | - Mordechai Segev
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ady Arie
- School of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gadi Eisenstein
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Peter Hommelhoff
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstraße 1, Erlangen 91058, Germany
| | - Ido Kaminer
- Department of Electrical Engineering, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
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39
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Karnieli A, Rivera N, Arie A, Kaminer I. Superradiance and Subradiance due to Quantum Interference of Entangled Free Electrons. PHYSICAL REVIEW LETTERS 2021; 127:060403. [PMID: 34420316 DOI: 10.1103/physrevlett.127.060403] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
When multiple quantum emitters radiate, their emission rate may be enhanced or suppressed due to collective interference in a process known as super- or subradiance. Such processes are well known to occur also in light emission from free electrons, known as coherent cathodoluminescence. Unlike atomic systems, free electrons have an unbounded energy spectrum, and, thus, all their emission mechanisms rely on electron recoil, in addition to the classical properties of the dielectric medium. To date, all experimental and theoretical studies of super- and subradiance from free electrons assumed only classical correlations between particles. However, dependence on quantum correlations, such as entanglement between free electrons, has not been studied. Recent advances in coherent shaping of free-electron wave functions motivate the investigation of such quantum regimes of super- and subradiance. In this Letter, we show how a pair of coincident path-entangled electrons can demonstrate either super- or subradiant light emission, depending on the two-particle wave function. By choosing different free-electron Bell states, the spectrum and emission pattern of the light can be reshaped, in a manner that cannot be accounted for by a classical mixed state. We show these results for light emission in any optical medium and discuss their generalization to many-body quantum states. Our findings suggest that light emission can be sensitive to the explicit quantum state of the emitting matter wave and possibly serve as a nondestructive measurement scheme for measuring the quantum state of many-body systems.
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Affiliation(s)
- Aviv Karnieli
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel
| | - Nicholas Rivera
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Ady Arie
- School of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ido Kaminer
- Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
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40
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Konečná A, Iyikanat F, García de Abajo FJ. Theory of Atomic-Scale Vibrational Mapping and Isotope Identification with Electron Beams. ACS NANO 2021; 15:9890-9899. [PMID: 34006088 DOI: 10.1021/acsnano.1c01071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Transmission electron microscopy and spectroscopy currently enable the acquisition of spatially resolved spectral information from a specimen by focusing electron beams down to a sub-angstrom spot and then analyzing the energy of the inelastically scattered electrons with few-meV energy resolution. This technique has recently been used to experimentally resolve vibrational modes in 2D materials emerging at mid-infrared frequencies. Here, on the basis of first-principles theory, we demonstrate the possibility of identifying single isotope atom impurities in a nanostructure through the trace that they leave in the spectral and spatial characteristics of the vibrational modes. Specifically, we examine a hexagonal boron nitride molecule as an example of application, in which the presence of a single isotope impurity is revealed through changes in the electron spectra, as well as in the space-, energy-, and momentum-resolved inelastic electron signal. We compare these results with conventional far-field spectroscopy, showing that electron beams offer superior spatial resolution combined with the ability to probe the complete set of vibrational modes, including those that are optically dark. Our study is relevant for the atomic-scale characterization of vibrational modes in materials of interest, including a detailed mapping of isotope distributions.
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Affiliation(s)
- Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Fadil Iyikanat
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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41
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Zhang B, Ran D, Ianconescu R, Friedman A, Scheuer J, Yariv A, Gover A. Quantum Wave-Particle Duality in Free-Electron-Bound-Electron Interaction. PHYSICAL REVIEW LETTERS 2021; 126:244801. [PMID: 34213937 DOI: 10.1103/physrevlett.126.244801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/08/2021] [Indexed: 06/13/2023]
Abstract
We present a comprehensive relativistic quantum-mechanical theory for interaction of a free electron with a bound electron in a model, where the free electron is represented as a finite-size quantum electron wave packet (QEW) and the bound electron is modeled by a quantum two-level system (TLS). The analysis reveals the wave-particle duality nature of the QEW, delineating the point-particle-like and wavelike interaction regimes and manifesting the physical reality of the wave function dimensions when interacting with matter. This QEW size dependence may be used for interrogation and coherent control of superposition states in a TLS and for enhancement of cathodoluminescence and electron energy-loss spectroscopy in electron microscopy.
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Affiliation(s)
- Bin Zhang
- Department of Electrical Engineering Physical Electronics, Center for Laser-Matter Interaction (LMI), Tel Aviv University, Ramat Aviv 69978, Israel
| | - Du Ran
- Department of Electrical Engineering Physical Electronics, Center for Laser-Matter Interaction (LMI), Tel Aviv University, Ramat Aviv 69978, Israel
- School of Electronic Information Engineering, Yangtze Normal University, Chongqing 408100, China
| | - Reuven Ianconescu
- Department of Electrical Engineering Physical Electronics, Center for Laser-Matter Interaction (LMI), Tel Aviv University, Ramat Aviv 69978, Israel
- Shenkar College of Engineering and Design, 12, Anna Frank Street, Ramat Gan 5252626, Israel
| | | | - Jacob Scheuer
- Department of Electrical Engineering Physical Electronics, Center for Laser-Matter Interaction (LMI), Tel Aviv University, Ramat Aviv 69978, Israel
| | - Amnon Yariv
- California Institute of Technology, Pasadena, California 91125, USA
| | - Avraham Gover
- Department of Electrical Engineering Physical Electronics, Center for Laser-Matter Interaction (LMI), Tel Aviv University, Ramat Aviv 69978, Israel
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42
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Di Giulio V, Kfir O, Ropers C, García de Abajo FJ. Modulation of Cathodoluminescence Emission by Interference with External Light. ACS NANO 2021; 15:7290-7304. [PMID: 33724007 PMCID: PMC8939848 DOI: 10.1021/acsnano.1c00549] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/18/2021] [Indexed: 05/20/2023]
Abstract
Spontaneous processes triggered in a sample by free electrons, such as cathodoluminescence, are commonly regarded and detected as stochastic events. Here, we supplement this picture by showing through first-principles theory that light and free-electron pulses can interfere when interacting with a nanostructure, giving rise to a modulation in the spectral distribution of the cathodoluminescence light emission that is strongly dependent on the electron wave function. Specifically, for a temporally focused electron, cathodoluminescence can be canceled upon illumination with a spectrally modulated dimmed laser that is phase-locked relative to the electron density profile. We illustrate this idea with realistic simulations under attainable conditions in currently available ultrafast electron microscopes. We further argue that the interference between excitations produced by light and free electrons enables the manipulation of the ultrafast materials response by combining the spectral and temporal selectivity of the light with the atomic resolution of electron beams.
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Affiliation(s)
- Valerio Di Giulio
- ICFO-Institut de
Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Ofer Kfir
- IV Physical Institute,
Solids and Nanostructures, University of
Göttingen, 37077 Göttingen, Germany
- Max Planck
Institute for Biophysical Chemistry (MPIBPC), 37077 Göttingen, Germany
| | - Claus Ropers
- IV Physical Institute,
Solids and Nanostructures, University of
Göttingen, 37077 Göttingen, Germany
- Max Planck
Institute for Biophysical Chemistry (MPIBPC), 37077 Göttingen, Germany
| | - F. Javier García de Abajo
- ICFO-Institut de
Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis
Avançats, Passeig
Lluís Companys 23, 08010 Barcelona, Spain
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43
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Kfir O, Di Giulio V, de Abajo FJG, Ropers C. Optical coherence transfer mediated by free electrons. SCIENCE ADVANCES 2021; 7:eabf6380. [PMID: 33931451 PMCID: PMC8087403 DOI: 10.1126/sciadv.abf6380] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/16/2021] [Indexed: 05/03/2023]
Abstract
We theoretically investigate the quantum-coherence properties of the cathodoluminescence (CL) emission produced by a temporally modulated electron beam. Specifically, we consider the quantum-optical correlations of CL produced by electrons that are previously shaped by a laser field. Our main prediction is the presence of phase correlations between the emitted CL field and the electron-modulating laser, even though the emission intensity and spectral profile are independent of the electron state. In addition, the coherence of the CL field extends to harmonics of the laser frequency. Since electron beams can be focused to below 1 Å, their ability to transfer optical coherence could enable the ultra-precise excitation, manipulation, and spectrally resolved probing of nanoscale quantum systems.
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Affiliation(s)
- Ofer Kfir
- University of Göttingen, IV. Physical Institute, Göttingen, Germany.
- Max Planck Institute for Biophysical Chemistry (MPIBPC), Göttingen, Germany
| | - Valerio Di Giulio
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Claus Ropers
- University of Göttingen, IV. Physical Institute, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry (MPIBPC), Göttingen, Germany
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44
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Mkhitaryan V, March K, Tseng EN, Li X, Scarabelli L, Liz-Marzán LM, Chen SY, Tizei LHG, Stéphan O, Song JM, Kociak M, García de Abajo FJ, Gloter A. Can Copper Nanostructures Sustain High-Quality Plasmons? NANO LETTERS 2021; 21:2444-2452. [PMID: 33651617 DOI: 10.1021/acs.nanolett.0c04667] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Silver, king among plasmonic materials, features low inelastic absorption in the visible-infrared (vis-IR) spectral region compared to other metals. In contrast, copper is commonly regarded as too lossy for actual applications. Here, we demonstrate vis-IR plasmons with quality factors >60 in long copper nanowires (NWs), as determined by electron energy-loss spectroscopy. We explain this result by noticing that most of the electromagnetic energy in these plasmons lies outside the metal, thus becoming less sensitive to inelastic absorption. Measurements for silver and copper NWs of different diameters allow us to elucidate the relative importance of radiative and nonradiative losses in plasmons spanning a wide spectral range down to <20 meV. Thermal population of such low-energy modes becomes significant and generates electron energy gains associated with plasmon absorption, rendering an experimental determination of the NW temperature. Copper is therefore emerging as an attractive, cheap, abundant material platform for high-quality plasmonics in elongated nanostructures.
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Affiliation(s)
- Vahagn Mkhitaryan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain
| | - Katia March
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Eric Nestor Tseng
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Xiaoyan Li
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Leonardo Scarabelli
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 38013 Bilbao, Spain
- Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Paseo de Miramón 182, 28014 Donostia-San Sebastián, Spain
| | - Shih-Yun Chen
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Luiz H G Tizei
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Odile Stéphan
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Jenn-Ming Song
- Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan
| | - Mathieu Kociak
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Alexandre Gloter
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
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