1
|
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.
Collapse
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
| |
Collapse
|
2
|
Bertoni G, Rotunno E, Marsmans D, Tiemeijer P, Tavabi AH, Dunin-Borkowski RE, Grillo V. Near-real-time diagnosis of electron optical phase aberrations in scanning transmission electron microscopy using an artificial neural network. Ultramicroscopy 2023; 245:113663. [PMID: 36566529 DOI: 10.1016/j.ultramic.2022.113663] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 10/17/2022] [Accepted: 12/17/2022] [Indexed: 12/23/2022]
Abstract
The key to optimizing spatial resolution in a state-of-the-art scanning transmission electron microscope is the ability to measure and correct for electron optical aberrations of the probe-forming lenses precisely. Several diagnostic methods for aberration measurement and correction have been proposed, albeit often at the cost of relatively long acquisition times. Here, we illustrate how artificial intelligence can be used to provide near-real-time diagnosis of aberrations from individual Ronchigrams. The demonstrated speed of aberration measurement is important because microscope conditions can change rapidly. It is also important for the operation of MEMS-based hardware correction elements, which have less intrinsic stability than conventional electromagnetic lenses.
Collapse
Affiliation(s)
- Giovanni Bertoni
- Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/A, 41125 Modena, Italy.
| | - Enzo Rotunno
- Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/A, 41125 Modena, Italy.
| | - Daan Marsmans
- Thermo Fisher Scientific, PO Box 80066, 5600 KA Eindhoven, the Netherlands
| | - Peter Tiemeijer
- Thermo Fisher Scientific, PO Box 80066, 5600 KA Eindhoven, the Netherlands
| | - Amir H Tavabi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Vincenzo Grillo
- Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/A, 41125 Modena, Italy
| |
Collapse
|
3
|
Planas XB, Ordóñez A, Lewenstein M, Maxwell AS. Ultrafast Imaging of Molecular Chirality with Photoelectron Vortices. PHYSICAL REVIEW LETTERS 2022; 129:233201. [PMID: 36563195 DOI: 10.1103/physrevlett.129.233201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 07/30/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
Ultrafast imaging of molecular chirality is a key step toward the dream of imaging and interpreting electronic dynamics in complex and biologically relevant molecules. Here, we propose a new ultrafast chiral phenomenon exploiting recent advances in electron optics allowing access to the orbital angular momentum of free electrons. We show that strong-field ionization of a chiral target with a few-cycle linearly polarized 800 nm laser pulse yields photoelectron vortices, whose chirality reveals that of the target, and we discuss the mechanism underlying this phenomenon. Our Letter opens new perspectives in recollision-based chiral imaging.
Collapse
Affiliation(s)
- Xavier Barcons Planas
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Andrés Ordóñez
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Maciej Lewenstein
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA, Passeig de Lluís Companys 23, 08010 Barcelona, Spain
| | - Andrew S Maxwell
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Maxwell AS, Madsen LB, Lewenstein M. Entanglement of orbital angular momentum in non-sequential double ionization. Nat Commun 2022; 13:4706. [PMID: 35948552 PMCID: PMC9365801 DOI: 10.1038/s41467-022-32128-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 07/19/2022] [Indexed: 11/30/2022] Open
Abstract
Entanglement has a capacity to enhance imaging procedures, but this remains unexplored for attosecond imaging. Here, we elucidate that possibility, addressing orbital angular momentum (OAM) entanglement in ultrafast processes. In the correlated process non-sequential double ionization (NSDI) we demonstrate robust photoelectron entanglement. In contrast to commonly considered continuous variables, the discrete OAM allows for a simpler interpretation, computation, and measurement of entanglement. The logarithmic negativity reveals that the entanglement is robust to incoherence and an entanglement witness minimizes the number of measurements to detect the entanglement, both quantities are related to OAM coherence terms. We quantify the entanglement for a range of targets and field parameters to find the most entangled photoelectron pairs. This methodology provides a general way to use OAM to quantify and measure entanglement, well-suited to attosecond processes, and can be exploited to enhance imaging capabilities through correlated measurements, or for generation of OAM-entangled electrons. In strong field ionization, entanglement between an electron and an ion has been discussed previously. Here the authors explore orbital angular momentum entanglement between the electrons released in non-sequential double ionization.
Collapse
Affiliation(s)
- Andrew S Maxwell
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain. .,Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark.
| | - Lars Bojer Madsen
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - Maciej Lewenstein
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain.,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
| |
Collapse
|
6
|
Gargiulo S, Madan I, Carbone F. Nuclear Excitation by Electron Capture in Excited Ions. PHYSICAL REVIEW LETTERS 2022; 128:212502. [PMID: 35687469 DOI: 10.1103/physrevlett.128.212502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/10/2021] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
A nuclear excitation following the capture of an electron in an empty orbital has been recently observed for the first time. So far, the evaluation of the cross section of the process has been carried out widely using the assumption that the ion is in its electronic ground state prior to the capture. We show that by lifting this restriction new capture channels emerge resulting in a boost of more than three orders of magnitude to the electron capture resonance strength.
Collapse
Affiliation(s)
- Simone Gargiulo
- Institute of Physics (IPhys), Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015 CH, Switzerland
| | - Ivan Madan
- Institute of Physics (IPhys), Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015 CH, Switzerland
| | - Fabrizio Carbone
- Institute of Physics (IPhys), Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015 CH, Switzerland
| |
Collapse
|
7
|
Löffler S. Unitary two-state quantum operators realized by quadrupole fields in the electron microscope. Ultramicroscopy 2022; 234:113456. [PMID: 35032788 DOI: 10.1016/j.ultramic.2021.113456] [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: 09/10/2021] [Revised: 11/26/2021] [Accepted: 12/05/2021] [Indexed: 10/19/2022]
Abstract
In this work, a novel method for using a set of electromagnetic quadrupole fields is presented to implement arbitrary unitary operators on a two-state quantum system of electrons. In addition to analytical derivations of the required quadrupole and beam settings which allow an easy direct implementation, numerical simulations of realistic scenarios show the feasibility of the proposed setup. This is expected to pave the way not only for new measurement schemes in electron microscopy and related fields but even one day for the implementation of quantum computing in the electron microscope.
Collapse
Affiliation(s)
- Stefan Löffler
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10/E057-02, 1040, Wien, Austria.
| |
Collapse
|
8
|
Roitman D, Shiloh R, Lu PH, Dunin-Borkowski RE, Arie A. Shaping of Electron Beams Using Sculpted Thin Films. ACS PHOTONICS 2021; 8:3394-3405. [PMID: 34938823 PMCID: PMC8679091 DOI: 10.1021/acsphotonics.1c00951] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/31/2021] [Accepted: 11/04/2021] [Indexed: 05/04/2023]
Abstract
Electron beam shaping by sculpted thin films relies on electron-matter interactions and the wave nature of electrons. It can be used to study physical phenomena of special electron beams and to develop technological applications in electron microscopy that offer new and improved measurement techniques and increased resolution in different imaging modes. In this Perspective, we review recent applications of sculpted thin films for electron orbital angular momentum sorting, improvements in phase contrast transmission electron microscopy, and aberration correction. For the latter, we also present new results of our work toward correction of the spherical aberration of Lorentz scanning transmission electron microscopes and suggest a method to correct chromatic aberration using thin films. This review provides practical insight for researchers in the field and motivates future progress in electron microscopy.
Collapse
Affiliation(s)
- Dolev Roitman
- School
of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roy Shiloh
- Physics
Department, Friedrich-Alexander-Universität
Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Peng-Han Lu
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter
Grünberg Institute, Forschungszentrum
Jülich, Jülich 52428, Germany
- RWTH
Aachen University, Aachen 52062, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter
Grünberg Institute, Forschungszentrum
Jülich, Jülich 52428, Germany
| | - Ady Arie
- School
of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| |
Collapse
|
9
|
Wang C, Ren Y, Liu T, Liu Z, Qiu S, Ding Y, Zhao J, Li R. Mode analyzer for known optical vortices from a spatial light modulator with collinear holography. APPLIED OPTICS 2021; 60:9706-9712. [PMID: 34807154 DOI: 10.1364/ao.438425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
The optical vortex has already found lots of applications in various domains. Among such applications, the precise and quantitative mode analysis of optical vortices is of great significance. In this work, we experimentally validate a simple method to analyze the mode of an already known optical field with collinear holography based on the phase-shifting technology. Further, we propose a ring interference strategy to improve the accuracy of mode analysis. In the proof-of-concept experiment, the complex amplitude is characterized, and the mode purity is well analyzed. This method has excellent accuracy and rapidity, which can be implemented in micro-manipulation, optical communication, and rotation speed measurement based on the rotating Doppler effect.
Collapse
|
10
|
Schachinger T, Hartel P, Lu PH, Löffler S, Obermair M, Dries M, Gerthsen D, Dunin-Borkowski RE, Schattschneider P. Experimental realization of a π/2 vortex mode converter for electrons using a spherical aberration corrector. Ultramicroscopy 2021; 229:113340. [PMID: 34311124 DOI: 10.1016/j.ultramic.2021.113340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 05/18/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
In light optics, beams with orbital angular momentum (OAM) can be produced by employing a properly-tuned two-cylinder-lens arrangement, also called π/2 mode converter. It is not possible to convey this concept directly to the beam in an electron microscope due to the non-existence of cylinder lenses in commercial transmission electron microscopes (TEMs). A viable work-around are readily-available electron optical elements in the form of quadrupole lenses. In a proof-of-principle experiment in 2012, it has been shown that a single quadrupole in combination with a Hilbert phase-plate produces a spatially-confined, transient vortex mode. Here, an analogue to an optical π/2 mode converter is realized by repurposing a CEOS DCOR probe corrector in an aberration corrected TEM in a way that it resembles a dual cylinder lens using two quadrupoles. In order to verify the presence of OAM in the output beam, a fork dislocation grating is used as an OAM analyser. The possibility to use magnetic quadrupole fields instead of, e.g., prefabricated fork dislocation gratings to produce electron beams carrying OAM enhances the beam brightness by almost an order of magnitude and delivers switchable high-mode purity vortex beams without unwanted side-bands.
Collapse
Affiliation(s)
- T Schachinger
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Wien, Austria; University Service Centre for Transmission Electron Microscopy (USTEM), TU Wien, Wiedner Hauptstraße 8-10, 1040 Wien, Austria.
| | - P Hartel
- CEOS Corrected Electron Optical Systems GmbH, Englerstraße 28, 69126 Heidelberg, Germany
| | - P-H Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; RWTH Aachen University, Ahornstraße 55, 52074 Aachen, Germany
| | - S Löffler
- University Service Centre for Transmission Electron Microscopy (USTEM), TU Wien, Wiedner Hauptstraße 8-10, 1040 Wien, Austria
| | - M Obermair
- Laboratorium für Elektronenmikroskopie (LEM), Karlsruher Institut für Technologie (KIT), Engesserstraße 7, 76131 Karlsruhe, Germany
| | - M Dries
- Laboratorium für Elektronenmikroskopie (LEM), Karlsruher Institut für Technologie (KIT), Engesserstraße 7, 76131 Karlsruhe, Germany
| | - D Gerthsen
- Laboratorium für Elektronenmikroskopie (LEM), Karlsruher Institut für Technologie (KIT), Engesserstraße 7, 76131 Karlsruhe, Germany
| | - R E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - P Schattschneider
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Wien, Austria; University Service Centre for Transmission Electron Microscopy (USTEM), TU Wien, Wiedner Hauptstraße 8-10, 1040 Wien, Austria
| |
Collapse
|
11
|
Zhang Y, Lu PH, Rotunno E, Troiani F, van Schayck JP, Tavabi AH, Dunin-Borkowski RE, Grillo V, Peters PJ, Ravelli RBG. Single-particle cryo-EM: alternative schemes to improve dose efficiency. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1343-1356. [PMID: 34475283 PMCID: PMC8415325 DOI: 10.1107/s1600577521007931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Imaging of biomolecules by ionizing radiation, such as electrons, causes radiation damage which introduces structural and compositional changes of the specimen. The total number of high-energy electrons per surface area that can be used for imaging in cryogenic electron microscopy (cryo-EM) is severely restricted due to radiation damage, resulting in low signal-to-noise ratios (SNR). High resolution details are dampened by the transfer function of the microscope and detector, and are the first to be lost as radiation damage alters the individual molecules which are presumed to be identical during averaging. As a consequence, radiation damage puts a limit on the particle size and sample heterogeneity with which electron microscopy (EM) can deal. Since a transmission EM (TEM) image is formed from the scattering process of the electron by the specimen interaction potential, radiation damage is inevitable. However, we can aim to maximize the information transfer for a given dose and increase the SNR by finding alternatives to the conventional phase-contrast cryo-EM techniques. Here some alternative transmission electron microscopy techniques are reviewed, including phase plate, multi-pass transmission electron microscopy, off-axis holography, ptychography and a quantum sorter. Their prospects for providing more or complementary structural information within the limited lifetime of the sample are discussed.
Collapse
Affiliation(s)
- Yue Zhang
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| | - Peng-Han Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Enzo Rotunno
- CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/A, I-41125 Modena, Italy
| | - Filippo Troiani
- CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/A, I-41125 Modena, Italy
| | - J. Paul van Schayck
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| | - Amir H. Tavabi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Vincenzo Grillo
- CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/A, I-41125 Modena, Italy
| | - Peter J. Peters
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| | - Raimond B. G. Ravelli
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, Maastricht 6229 ER, The Netherlands
| |
Collapse
|
12
|
Kang Y, Pisanty E, Ciappina M, Lewenstein M, Figueira de Morisson Faria C, Maxwell AS. Conservation laws for electron vortices in strong-field ionisation. THE EUROPEAN PHYSICAL JOURNAL. D, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 2021; 75:199. [PMID: 34720728 PMCID: PMC8550503 DOI: 10.1140/epjd/s10053-021-00214-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/27/2021] [Indexed: 06/13/2023]
Abstract
ABSTRACT We investigate twisted electrons with a well-defined orbital angular momentum, which have been ionised via a strong laser field. By formulating a new variant of the well-known strong field approximation, we are able to derive conservation laws for the angular momenta of twisted electrons in the cases of linear and circularly polarised fields. In the case of linear fields, we demonstrate that the orbital angular momentum of the twisted electron is determined by the magnetic quantum number of the initial bound state. The condition for the circular field can be related to the famous ATI peaks, and provides a new interpretation for this fundamental feature of photoelectron spectra. We find the length of the circular pulse to be a vital factor in this selection rule and, employing an effective frequency, we show that the photoelectron OAM emission spectra are sensitive to the parity of the number of laser cycles. This work provides the basic theoretical framework with which to understand the OAM of a photoelectron undergoing strong field ionisation.
Collapse
Affiliation(s)
- Yuxin Kang
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
| | - Emilio Pisanty
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain
| | - Marcelo Ciappina
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain
- Physics Program, Guangdong Technion – Israel Institute of Technology, Shantou, 515063 Guangdong China
- Technion – Israel Institute of Technology, 32000 Haifa, Israel
| | - Maciej Lewenstein
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | | | - Andrew S. Maxwell
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain
| |
Collapse
|
13
|
Alignment of electron optical beam shaping elements using a convolutional neural network. Ultramicroscopy 2021; 228:113338. [PMID: 34218137 DOI: 10.1016/j.ultramic.2021.113338] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 11/23/2022]
Abstract
A convolutional neural network is used to align an orbital angular momentum sorter in a transmission electron microscope. The method is demonstrated using simulations and experiments. As a result of its accuracy and speed, it offers the possibility of real-time tuning of other electron optical devices and electron beam shaping configurations.
Collapse
|
14
|
Maxwell AS, Armstrong GSJ, Ciappina MF, Pisanty E, Kang Y, Brown AC, Lewenstein M, Figueira de Morisson Faria C. Manipulating twisted electrons in strong-field ionization. Faraday Discuss 2021; 228:394-412. [PMID: 33591304 DOI: 10.1039/d0fd00105h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We investigate the discrete orbital angular momentum (OAM) of photoelectrons freed in strong-field ionization. We use these 'twisted' electrons to provide an alternative interpretation on existing experimental work of vortex interferences caused by strong field ionization mediated by two counter-rotating circularly polarized pulses separated by a delay. Using the strong field approximation, we derive an interference condition for the vortices. In computations for a neon target we find very good agreement of the vortex condition with photoelectron momentum distributions computed with the strong field approximation, as well as with the time-dependent methods Qprop and R-Matrix. For each of these approaches we examine the OAM of the photoelectrons, finding a small number of vortex states localized in separate energy regions. We demonstrate that the vortices arise from the interference of pairs of twisted electron states. The OAM of each twisted electron state can be directly related to the number of arms of the spiral in that region. We gain further understanding by recreating the vortices with pairs of twisted electrons and use this to determine a semiclassical relation for the OAM. A discussion is included on measuring the OAM in strong field ionization directly or by employing specific laser pulse schemes as well as utilizing the OAM in time-resolved imaging of photo-induced dynamics.
Collapse
Affiliation(s)
- A S Maxwell
- Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK. and ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - G S J Armstrong
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland, UK
| | - M F Ciappina
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain and Physics Program, Guangdong Technion - Israel Institute of Technology, Shantou, Guangdong 515063, China and Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - E Pisanty
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Y Kang
- Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
| | - A C Brown
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland, UK
| | - M Lewenstein
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain and ICREA, Pg. Lluís Companys 23, 08010, Spain
| | | |
Collapse
|
15
|
Pozzi G, Rosi P, Tavabi AH, Karimi E, Dunin-Borkowski RE, Grillo V. A sorter for electrons based on magnetic elements. Ultramicroscopy 2021; 231:113287. [PMID: 33926773 DOI: 10.1016/j.ultramic.2021.113287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 04/01/2021] [Accepted: 04/10/2021] [Indexed: 10/21/2022]
Abstract
The orbital angular momentum (OAM) sorter is an electron optical device for the measurement of an electron's OAM. It is based on two phase elements, which are referred to as an "unwrapper" and a "corrector" and are located in Fourier conjugate planes. The simplest implementation of the sorter is based on electrostatic phase elements, such as a charged needle for the unwrapper and electrodes with alternating charges or potentials for the corrector. Here, we use a formal analogy between phase shifts introduced by charges and vertical currents to propose alternative designs for the sorter elements, which are based on phase shifts introduced by magnetic fields. We use this concept to provide a general guide for phase element design, which promises to provide improved reliability of phase control in electron optics.
Collapse
Affiliation(s)
- Giulio Pozzi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Department of Physics and Astronomy, University of Bologna, viale B. Pichat 6/2, 40127 Bologna, Italy
| | - Paolo Rosi
- Department FIM, University of Modena and Reggio Emilia, via G. Campi 213/a, 41125 Modena, Italy
| | - Amir H Tavabi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Ebrahim Karimi
- Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Vincenzo Grillo
- Department FIM, University of Modena and Reggio Emilia, via G. Campi 213/a, 41125 Modena, Italy; CNR-Institute of Nanoscience-S3, via G. Campi 213/a, 41125 Modena, Italy.
| |
Collapse
|
16
|
Tavabi AH, Rosi P, Rotunno E, Roncaglia A, Belsito L, Frabboni S, Pozzi G, Gazzadi GC, Lu PH, Nijland R, Ghosh M, Tiemeijer P, Karimi E, Dunin-Borkowski RE, Grillo V. Experimental Demonstration of an Electrostatic Orbital Angular Momentum Sorter for Electron Beams. PHYSICAL REVIEW LETTERS 2021; 126:094802. [PMID: 33750150 DOI: 10.1103/physrevlett.126.094802] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/06/2020] [Accepted: 01/12/2021] [Indexed: 05/21/2023]
Abstract
The component of orbital angular momentum (OAM) in the propagation direction is one of the fundamental quantities of an electron wave function that describes its rotational symmetry and spatial chirality. Here, we demonstrate experimentally an electrostatic sorter that can be used to analyze the OAM states of electron beams in a transmission electron microscope. The device achieves postselection or sorting of OAM states after electron-material interactions, thereby allowing the study of new material properties such as the magnetic states of atoms. The required electron-optical configuration is achieved by using microelectromechanical systems technology and focused ion beam milling to control the electron phase electrostatically with a lateral resolution of 50 nm. An OAM resolution of 1.5ℏ is realized in tests on controlled electron vortex beams, with the perspective of reaching an optimal OAM resolution of 1ℏ in the near future.
Collapse
Affiliation(s)
- Amir H Tavabi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Paolo Rosi
- Dipartimento FIM, Universitá di Modena e Reggio Emilia, 41125 Modena, Italy
| | - Enzo Rotunno
- Centro S3, Istituto di Nanoscienze-CNR, 41125 Modena, Italy
| | - Alberto Roncaglia
- Istituto per la Microelettronica e i Microsistemi-CNR, 40129 Bologna, Italy
| | - Luca Belsito
- Istituto per la Microelettronica e i Microsistemi-CNR, 40129 Bologna, Italy
| | - Stefano Frabboni
- Dipartimento FIM, Universitá di Modena e Reggio Emilia, 41125 Modena, Italy
- Centro S3, Istituto di Nanoscienze-CNR, 41125 Modena, Italy
| | - Giulio Pozzi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
- Department of Physics and Astronomy, University of Bologna, 40127 Bologna, Italy
| | | | - Peng-Han Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
- RWTH Aachen University, 52074 Aachen, Germany
| | - Robert Nijland
- Thermo Fisher Scientific, PO Box 80066, 5600 KA Eindhoven, Netherlands
| | - Moumita Ghosh
- Thermo Fisher Scientific, PO Box 80066, 5600 KA Eindhoven, Netherlands
| | - Peter Tiemeijer
- Thermo Fisher Scientific, PO Box 80066, 5600 KA Eindhoven, Netherlands
| | - Ebrahim Karimi
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | | |
Collapse
|
17
|
Guido CA, Rotunno E, Zanfrognini M, Corni S, Grillo V. Exploring the Spatial Features of Electronic Transitions in Molecular and Biomolecular Systems by Swift Electrons. J Chem Theory Comput 2021; 17:2364-2373. [PMID: 33646769 PMCID: PMC8047794 DOI: 10.1021/acs.jctc.1c00045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
We
devise a new kind of experiment that extends the technology
of electron energy loss spectroscopy to probe (supra-)molecular systems: by using
an electron beam in a configuration that avoids
molecular damage and a very recently introduced electron optics setup
for the analysis of the outcoming electrons, one can obtain information
on the spatial features of the investigated excitations. Physical
insight into the proposed experiment is provided by means of a simple
but rigorous model to obtain the transition rate and selection rule.
Numerical simulations of DNA G-quadruplexes and other biomolecular
systems, based on time dependent density functional theory calculations,
point out that the conceived new technique can probe the multipolar
components and even the chirality of molecular transitions, superseding
the usual optical spectroscopies for those cases that are problematic,
such as dipole-forbidden transitions, at a very high spatial resolution.
Collapse
Affiliation(s)
- Ciro A Guido
- Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Enzo Rotunno
- CNR-NANO, Institute of Nanoscience, via Campi 213/A, Modena, Italy
| | | | - Stefano Corni
- Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo 1, 35131 Padova, Italy.,CNR-NANO, Institute of Nanoscience, via Campi 213/A, Modena, Italy
| | - Vincenzo Grillo
- CNR-NANO, Institute of Nanoscience, via Campi 213/A, Modena, Italy
| |
Collapse
|
18
|
Danz T, Domröse T, Ropers C. Ultrafast nanoimaging of the order parameter in a structural phase transition. Science 2021; 371:371-374. [DOI: 10.1126/science.abd2774] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Thomas Danz
- 4th Physical Institute – Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - Till Domröse
- 4th Physical Institute – Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - Claus Ropers
- 4th Physical Institute – Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| |
Collapse
|
19
|
van Nielen N, Hentschel M, Schilder N, Giessen H, Polman A, Talebi N. Electrons Generate Self-Complementary Broadband Vortex Light Beams Using Chiral Photon Sieves. NANO LETTERS 2020; 20:5975-5981. [PMID: 32643947 DOI: 10.1021/acs.nanolett.0c01964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Planar electron-driven photon sources have been recently proposed as miniaturized light sources, with prospects for ultrafast conjugate electron-photon microscopy and spectral interferometry. Such sources usually follow the symmetry of the electron-induced polarization: transition-radiation-based sources, for example, only generate p-polarized light. Here we demonstrate that the polarization, the bandwidth, and the directionality of photons can be tailored by utilizing photon-sieve-based structures. We design, fabricate, and characterize self-complementary chiral structures made of holes in an Au film and generate light vortex beams with specified angular momentum orders. The incoming electron interacting with the structure generates chiral surface plasmon polaritons on the structured Au surface that scatter into the far field. The outcoupled radiation interferes with transition radiation creating TE- and TM-polarized Laguerre-Gauss light beams with a chiral intensity distribution. The generated vortex light and its unique spatiotemporal features can form the basis for the generation of structured-light electron-driven photon sources.
Collapse
Affiliation(s)
- Nika van Nielen
- Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Mario Hentschel
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
| | - Nick Schilder
- Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Harald Giessen
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
| | - Albert Polman
- Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Nahid Talebi
- Institute of Experimental and Applied Physics, Christian Albrechts University, Leibnizstrasse 19, 24118 Kiel, Germany
| |
Collapse
|
20
|
Ruffato G, Massari M, Romanato F. Multiplication and division of the orbital angular momentum of light with diffractive transformation optics. LIGHT, SCIENCE & APPLICATIONS 2019; 8:113. [PMID: 31814970 PMCID: PMC6892886 DOI: 10.1038/s41377-019-0222-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 11/05/2019] [Accepted: 11/11/2019] [Indexed: 05/25/2023]
Abstract
We present a method to efficiently multiply or divide the orbital angular momentum (OAM) of light beams using a sequence of two optical elements. The key element is represented by an optical transformation mapping the azimuthal phase gradient of the input OAM beam onto a circular sector. By combining multiple circular-sector transformations into a single optical element, it is possible to multiply the value of the input OAM state by splitting and mapping the phase onto complementary circular sectors. Conversely, by combining multiple inverse transformations, the division of the initial OAM value is achievable by mapping distinct complementary circular sectors of the input beam into an equal number of circular phase gradients. Optical elements have been fabricated in the form of phase-only diffractive optics with high-resolution electron-beam lithography. Optical tests confirm the capability of the multiplier optics to perform integer multiplication of the input OAM, whereas the designed dividers are demonstrated to correctly split up the input beam into a complementary set of OAM beams. These elements can find applications for the multiplicative generation of higher-order OAM modes, optical information processing based on OAM beam transmission, and optical routing/switching in telecom.
Collapse
Affiliation(s)
- Gianluca Ruffato
- Department of Physics and Astronomy ‘G. Galilei’, University of Padova, via Marzolo 8, 35131 Padova, Italy
- LaNN, Laboratory for Nanofabrication of Nanodevices, EcamRicert, Corso StatiUniti 4, 35127 Padova, Italy
| | - Michele Massari
- LaNN, Laboratory for Nanofabrication of Nanodevices, EcamRicert, Corso StatiUniti 4, 35127 Padova, Italy
- CNR-INFM TASC IOM National Laboratory, S.S. 14 Km 163.5, 34012 Trieste, Italy
| | - Filippo Romanato
- Department of Physics and Astronomy ‘G. Galilei’, University of Padova, via Marzolo 8, 35131 Padova, Italy
- LaNN, Laboratory for Nanofabrication of Nanodevices, EcamRicert, Corso StatiUniti 4, 35127 Padova, Italy
- CNR-INFM TASC IOM National Laboratory, S.S. 14 Km 163.5, 34012 Trieste, Italy
| |
Collapse
|
21
|
Design of electrostatic phase elements for sorting the orbital angular momentum of electrons. Ultramicroscopy 2019; 208:112861. [PMID: 31670053 DOI: 10.1016/j.ultramic.2019.112861] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 11/22/2022]
Abstract
The orbital angular momentum (OAM) sorter is a new electron optical device for measuring an electron's OAM. It is based on two phase elements, which are referred to as the "unwrapper" and "corrector" and are placed in Fourier-conjugate planes in an electron microscope. The most convenient implementation of this concept is based on the use of electrostatic phase elements, such as a charged needle as the unwrapper and a set of electrodes with alternating charges as the corrector. Here, we use simulations to assess the role of imperfections in such a device, in comparison to an ideal sorter. We show that the finite length of the needle and the boundary conditions introduce astigmatism, which leads to detrimental cross-talk in the OAM spectrum. We demonstrate that an improved setup comprising three charged needles can be used to compensate for this aberration, allowing measurements with a level of cross-talk in the OAM spectrum that is comparable to the ideal case.
Collapse
|
22
|
Kramberger C, Löffler S, Schachinger T, Hartel P, Zach J, Schattschneider P. π/2 mode converters and vortex generators for electrons. Ultramicroscopy 2019; 204:27-33. [PMID: 31125763 DOI: 10.1016/j.ultramic.2019.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 05/07/2019] [Accepted: 05/12/2019] [Indexed: 10/26/2022]
Abstract
In optics, mode conversion is an elegant way to switch between Hermite Gaussian and Laguerre Gaussian beam profiles and thereby impart orbital angular momentum onto the beam and to create vortices. In optics such vortex beams can be produced in a setup consisting of two identical cylinder lenses. In electron optics, quadrupole lenses can be used for the same purpose. Here we investigate generalized asymmetric designs of a quadrupole mode converter that may be realized within the constraints of existing electron microscopes and can steer the development of dedicated vortex generators for high brilliance electron vortex probes of atomic scale.
Collapse
Affiliation(s)
- C Kramberger
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10/E138, Wien 1040, Austria.
| | - S Löffler
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10/E138, Wien 1040, Austria; University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10/E057-02, Wien 1040, Austria
| | - T Schachinger
- University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10/E057-02, Wien 1040, Austria
| | - P Hartel
- CEOS Corrected Electron Optical Systems GmbH, Englerstraße 28, Heidelberg 69126, Germany
| | - J Zach
- CEOS Corrected Electron Optical Systems GmbH, Englerstraße 28, Heidelberg 69126, Germany
| | - P Schattschneider
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10/E138, Wien 1040, Austria; University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10/E057-02, Wien 1040, Austria.
| |
Collapse
|
23
|
Vanacore GM, Berruto G, Madan I, Pomarico E, Biagioni P, Lamb RJ, McGrouther D, Reinhardt O, Kaminer I, Barwick B, Larocque H, Grillo V, Karimi E, García de Abajo FJ, Carbone F. Ultrafast generation and control of an electron vortex beam via chiral plasmonic near fields. NATURE MATERIALS 2019; 18:573-579. [PMID: 31061485 DOI: 10.1038/s41563-019-0336-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 03/07/2019] [Indexed: 05/27/2023]
Abstract
Vortex-carrying matter waves, such as chiral electron beams, are of significant interest in both applied and fundamental science. Continuous-wave electron vortex beams are commonly prepared via passive phase masks imprinting a transverse phase modulation on the electron's wavefunction. Here, we show that femtosecond chiral plasmonic near fields enable the generation and dynamic control on the ultrafast timescale of an electron vortex beam. The vortex structure of the resulting electron wavepacket is probed in both real and reciprocal space using ultrafast transmission electron microscopy. This method offers a high degree of scalability to small length scales and a highly efficient manipulation of the electron vorticity with attosecond precision. Besides the direct implications in the investigation of nanoscale ultrafast processes in which chirality plays a major role, we further discuss the perspectives of using this technique to shape the wavefunction of charged composite particles, such as protons, and how it can be used to probe their internal structure.
Collapse
Affiliation(s)
- G M Vanacore
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - G Berruto
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - I Madan
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - E Pomarico
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - P Biagioni
- Dipartimento di Fisica, Politecnico di Milano, Milano, Italy
| | - R J Lamb
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - D McGrouther
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - O Reinhardt
- Faculty of Electrical Engineering and Solid State Institute, Technion, Haifa, Israel
| | - I Kaminer
- Faculty of Electrical Engineering and Solid State Institute, Technion, Haifa, Israel
| | | | - H Larocque
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
| | - V Grillo
- CNR-Istituto Nanoscienze, Centro S3, Modena, Italy
| | - E Karimi
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
| | - F J 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
| | - F Carbone
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| |
Collapse
|
24
|
Fontaine NK, Ryf R, Chen H, Neilson DT, Kim K, Carpenter J. Laguerre-Gaussian mode sorter. Nat Commun 2019; 10:1865. [PMID: 31028257 PMCID: PMC6486581 DOI: 10.1038/s41467-019-09840-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 03/25/2019] [Indexed: 11/25/2022] Open
Abstract
Exploiting a particular wave property for a particular application necessitates components capable of discriminating in the basis of that property. While spectral or polarisation decomposition can be straightforward, spatial decomposition is inherently more difficult and few options exist regardless of wave type. Fourier decomposition by a lens is a rare simple example of a spatial decomposition of great practical importance and practical simplicity; a two-dimensional decomposition of a beam into its linear momentum components. Yet this is often not the most appropriate spatial basis. Previously, no device existed capable of a two-dimensional decomposition into orbital angular momentum components, or indeed any discrete basis, despite it being a fundamental property in many wave phenomena. We demonstrate an optical device capable of decomposing a beam into a Cartesian grid of identical Gaussian spots each containing a single Laguerre-Gaussian component, using just a spatial light modulator and mirror.
Collapse
Affiliation(s)
| | - Roland Ryf
- Nokia Bell Labs, 791 Holmdel Rd., Holmdel, NJ, 07722, USA
| | - Haoshuo Chen
- Nokia Bell Labs, 791 Holmdel Rd., Holmdel, NJ, 07722, USA
| | | | - Kwangwoong Kim
- Nokia Bell Labs, 791 Holmdel Rd., Holmdel, NJ, 07722, USA
| | - Joel Carpenter
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia.
| |
Collapse
|
25
|
Zhang K, Yuan Y, Zhang D, Ding X, Ratni B, Burokur SN, Lu M, Tang K, Wu Q. Phase-engineered metalenses to generate converging and non-diffractive vortex beam carrying orbital angular momentum in microwave region. OPTICS EXPRESS 2018; 26:1351-1360. [PMID: 29402010 DOI: 10.1364/oe.26.001351] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/09/2018] [Indexed: 06/07/2023]
Abstract
In this paper, ultra-thin metalenses are proposed to generate converging and non-diffractive vortex beam carrying orbital angular momentum (OAM) in microwave region. Phase changes are introduced to the transmission cross-polarized wave by tailoring spatial orientation of Pancharatnam-Berry phase unit cell. Based on the superposition of phase profile of spiral phase plate and that of a converging lens or an axicon, vortex beam carrying OAM mode generated by the metalens can also exhibit characteristics of a focusing beam or a Bessel beam. Measured field intensities and phase distributions at microwave frequencies verify the theoretical design procedure. The proposed method provides an efficient approach to control the radius of vortex beam carrying OAM mode in microwave wireless applications for medium-short range distance.
Collapse
|
26
|
Grillo V, Tavabi AH, Yucelen E, Lu PH, Venturi F, Larocque H, Jin L, Savenko A, Gazzadi GC, Balboni R, Frabboni S, Tiemeijer P, Dunin-Borkowski RE, Karimi E. Towards a holographic approach to spherical aberration correction in scanning transmission electron microscopy. OPTICS EXPRESS 2017; 25:21851-21860. [PMID: 29041477 DOI: 10.1364/oe.25.021851] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/11/2017] [Indexed: 06/07/2023]
Abstract
Recent progress in phase modulation using nanofabricated electron holograms has demonstrated how the phase of an electron beam can be controlled. In this paper, we apply this concept to the correction of spherical aberration in a scanning transmission electron microscope and demonstrate an improvement in spatial resolution. Such a holographic approach to spherical aberration correction is advantageous for its simplicity and cost-effectiveness.
Collapse
|
27
|
Larocque H, Gagnon-Bischoff J, Mortimer D, Zhang Y, Bouchard F, Upham J, Grillo V, Boyd RW, Karimi E. Generalized optical angular momentum sorter and its application to high-dimensional quantum cryptography. OPTICS EXPRESS 2017; 25:19832-19843. [PMID: 29041670 DOI: 10.1364/oe.25.019832] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
The orbital angular momentum (OAM) carried by optical beams is a useful quantity for encoding information. This form of encoding has been incorporated into various works ranging from telecommunications to quantum cryptography, most of which require methods that can rapidly process the OAM content of a beam. Among current state-of-the-art schemes that can readily acquire this information are so-called OAM sorters, which consist of devices that spatially separate the OAM components of a beam. Such devices have found numerous applications in optical communications, a field that is in constant demand for additional degrees of freedom, such as polarization and wavelength, into which information can also be encoded. Here, we report the implementation of a device capable of sorting a beam based on its OAM and polarization content, which could be of use in works employing both of these degrees of freedom as information channels. After characterizing our fabricated device, we demonstrate how it can be used for quantum communications via a quantum key distribution protocol.
Collapse
|
28
|
McMorran BJ, Agrawal A, Ercius PA, Grillo V, Herzing AA, Harvey TR, Linck M, Pierce JS. Origins and demonstrations of electrons with orbital angular momentum. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2015.0434. [PMID: 28069765 PMCID: PMC5247478 DOI: 10.1098/rsta.2015.0434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/28/2016] [Indexed: 05/14/2023]
Abstract
The surprising message of Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)) was that photons could possess orbital angular momentum in free space, which subsequently launched advancements in optical manipulation, microscopy, quantum optics, communications, many more fields. It has recently been shown that this result also applies to quantum mechanical wave functions describing massive particles (matter waves). This article discusses how electron wave functions can be imprinted with quantized phase vortices in analogous ways to twisted light, demonstrating that charged particles with non-zero rest mass can possess orbital angular momentum in free space. With Allen et al. as a bridge, connections are made between this recent work in electron vortex wave functions and much earlier works, extending a 175 year old tradition in matter wave vortices.This article is part of the themed issue 'Optical orbital angular momentum'.
Collapse
Affiliation(s)
| | - Amit Agrawal
- Center for Nanoscale Science and Technology, National Institute of Standards Technology, Gaithersburg, MD 20899, USA
- Maryland NanoCenter, University of Maryland, College Park, MD 20742, USA
| | - Peter A Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Vincenzo Grillo
- Department of Physics, University of Oregon, Eugene, OR, USA
- CNR-Istituto Nanoscienze, Centro S3, Via G. Campi 213/a, 41125 Modena, Italy
| | - Andrew A Herzing
- Materials Measurement Laboratory, National Institute of Standards Technology, Gaithersburg, MD 20899, USA
| | - Tyler R Harvey
- Department of Physics, University of Oregon, Eugene, OR, USA
| | - Martin Linck
- Corrected Electron Optical Systems GmbH, Englerstraße 28, 69126 Heidelberg, Germany
| | - Jordan S Pierce
- Department of Physics, University of Oregon, Eugene, OR, USA
| |
Collapse
|