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Bucher T, Ruimy R, Tsesses S, Dahan R, Bartal G, Vanacore GM, Kaminer I. Free-electron Ramsey-type interferometry for enhanced amplitude and phase imaging of nearfields. SCIENCE ADVANCES 2023; 9:eadi5729. [PMID: 38134276 PMCID: PMC10745688 DOI: 10.1126/sciadv.adi5729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023]
Abstract
The complex range of interactions between electrons and electromagnetic fields gave rise to countless scientific and technological advances. A prime example is photon-induced nearfield electron microscopy (PINEM), enabling the detection of confined electric fields in illuminated nanostructures with unprecedented spatial resolution. However, PINEM is limited by its dependence on strong fields, making it unsuitable for sensitive samples, and its inability to resolve complex phasor information. Here, we leverage the nonlinear, overconstrained nature of PINEM to present an algorithmic microscopy approach, achieving far superior nearfield imaging capabilities. Our algorithm relies on free-electron Ramsey-type interferometry to produce orders-of-magnitude improvement in sensitivity and ambiguity-immune nearfield phase reconstruction, both of which are optimal when the electron exhibits a fully quantum behavior. Our results demonstrate the potential of combining algorithmic approaches with state-of-the-art modalities in electron microscopy and may lead to various applications from imaging sensitive biological samples to performing full-field tomography of confined light.
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Affiliation(s)
- Tomer Bucher
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Ron Ruimy
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Shai Tsesses
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Raphael Dahan
- Solid State Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Guy Bartal
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Giovanni Maria Vanacore
- Department of Material Science, University of Milano-Bicocca, Via Cozzi 55, 20121 Milano, Italy
| | - Ido Kaminer
- Andrew and Erna Viterbi Department of Electrical and Computer Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Solid State Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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Mazor Y, Kfir O. Sub-terahertz nearfields for electron-pulse compression. OPTICS EXPRESS 2023; 31:37980-37992. [PMID: 38017916 DOI: 10.1364/oe.502407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/02/2023] [Indexed: 11/30/2023]
Abstract
The advent of ultrafast science with pulsed electron beams raised the need to control the temporal features of the electron pulses. One promising suggestion is the nano-selective quantum optics with multi-electrons, which scales quadratically with the number of electrons within the coherence time of the quantum system. Terahertz (THz) radiation from optical nonlinear crystals is an attractive methodology to generate the rapidly varying electric fields necessary for electron compression, with the advantage of an inherent temporal locking to laser-triggered electrons, such as in ultrafast electron microscopes. Longer (picosecond-) pulses require a sub-THz field for their compression. However, the generation of such low frequencies requires pumping with energetic optical pulses and their focusability is fundamentally limited by their mm-wavelength. This work proposes electron-pulse compression with sub-THz fields directly in the vicinity of their dipolar origin, thereby avoiding mediation through radiation. We analyze the merits of nearfields for compression of slow electrons, particularly in challenging regimes for THz radiation, such as small numerical apertures, micro-joule-level optical pump pulses, and low frequencies. This scheme can be implemented within the tight constraints of electron microscopes and reach fields of a few kV/cm below 0.1 THz at high repetition rates. Our paradigm offers a realistic approach for controlling electron pulses spatially and temporally in many experiments, opening the path of flexible multi-electron manipulation for analytic and quantum sciences.
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Iwasaki Y, Akase Z, Shimada K, Harada K, Shindo D. Time-resolved electron holography and its application to an ionic liquid specimen. Microscopy (Oxf) 2023; 72:455-459. [PMID: 36629509 PMCID: PMC10561666 DOI: 10.1093/jmicro/dfad003] [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: 11/29/2022] [Revised: 12/29/2022] [Accepted: 01/10/2023] [Indexed: 01/12/2023] Open
Abstract
Time-resolved electron holography was implemented in a transmission electron microscope by means of electron beam gating with a parallel-plate electrostatic deflector. Stroboscopic observations were performed by accumulating gated electron interference images while applying a periodic modulation voltage to a specimen. Electric polarization in an ionic liquid specimen was observed under applied fields. While a static electric field in the specimen was reduced by the polarization of the material, an applied field modulated at 10 kHz was not screened. This indicates that time-resolved electron holography is capable of determining the frequency limit of dynamic response of polarization in materials. Graphical Abstract.
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Affiliation(s)
- Yoh Iwasaki
- Center for Emergent Matter Science, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Zentaro Akase
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Keiko Shimada
- Center for Emergent Matter Science, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Ken Harada
- Center for Emergent Matter Science, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Daisuke Shindo
- Center for Emergent Matter Science, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Weßels T, Däster S, Murooka Y, Zingsem B, Migunov V, Kruth M, Finizio S, Lu PH, Kovács A, Oelsner A, Müller-Caspary K, Acremann Y, Dunin-Borkowski RE. Continuous illumination picosecond imaging using a delay line detector in a transmission electron microscope. Ultramicroscopy 2022; 233:113392. [PMID: 35016129 DOI: 10.1016/j.ultramic.2021.113392] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/04/2021] [Accepted: 09/09/2021] [Indexed: 11/28/2022]
Abstract
Progress towards analysing transitions between steady states demands improvements in time-resolved imaging, both for fundamental research and for applications in information technology. Transmission electron microscopy is a powerful technique for investigating the atomic structure, chemical composition and electromagnetic properties of materials with high spatial resolution and precision. However, the extraction of information about dynamic processes in the ps time regime is often not possible without extensive modification to the instrument while requiring careful control of the operation conditions to not compromise the beam quality. Here, we avoid these drawbacks by combining a delay line detector with continuous illumination in a transmission electron microscope. We visualize the gyration of a magnetic vortex core in real space and show that magnetization dynamics up to frequencies of 2.3 GHz can be resolved with down to ∼122ps temporal resolution by studying the interaction of an electron beam with a microwave magnetic field. In the future, this approach promises to provide access to resonant dynamics by combining high spatial resolution with sub-ns temporal resolution.
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Affiliation(s)
- Teresa Weßels
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Lehrstuhl für Experimentalphysik IV E, RWTH Aachen University, 52056 Aachen, Germany.
| | - Simon Däster
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Yoshie Murooka
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Benjamin Zingsem
- Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Vadim Migunov
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Central Facility for Electron Microscopy (GFE), RWTH Aachen University, 52074 Aachen, Germany
| | - Maximilian Kruth
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Peng-Han Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | | | - Knut Müller-Caspary
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - Yves Acremann
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
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Cho Y, Lee S, Murakami Y. Magnetic flux density measurements from narrow grain boundaries produced in sintered permanent magnets. Microscopy (Oxf) 2021; 70:17-23. [PMID: 32572498 DOI: 10.1093/jmicro/dfaa032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/11/2020] [Accepted: 06/19/2020] [Indexed: 11/13/2022] Open
Abstract
This review examines methods of magnetic flux density measurements from the narrow grain boundary (GB) regions, the thickness of which is of the order of nanometers, produced in Nd-Fe-B-based sintered magnets. Despite of the complex crystallographic microstructure and the significant stray magnetic field of the sintered magnet, recent progress in electron holography allowed for the determination of the intrinsic magnetic flux density due to the GB which is embedded in the polycrystalline thin-foil. The methods appear to be useful as well for intensive studies about interface magnetism in a variety of systems.
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Affiliation(s)
- Youngji Cho
- The Ultramicroscopy Research Center, Kyushu University, Fukuoka 819-0395, Japan
| | - Sujin Lee
- Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Yasukazu Murakami
- The Ultramicroscopy Research Center, Kyushu University, Fukuoka 819-0395, Japan.,Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
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Olshin PK, Drabbels M, Lorenz UJ. Characterization of a time-resolved electron microscope with a Schottky field emission gun. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:054304. [PMID: 33062804 PMCID: PMC7532021 DOI: 10.1063/4.0000034] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/07/2020] [Indexed: 05/27/2023]
Abstract
The rapid growth of the field of time-resolved and ultrafast electron microscopy has been accompanied by the active development of new instrumentation. Recently, time-resolved microscopes equipped with a field emission gun have been introduced, demonstrating great potential for experiments that benefit from the high brightness and coherence of the electron source. Here, we describe a straightforward design of a time-resolved transmission electron microscope with a Schottky field emission gun and characterize its performance. At the same time, our design gives us the flexibility to alternatively operate the instrument as if it was equipped with a flat metal photocathode. We can, thus, effectively choose to sacrifice brightness in order to obtain pulses with vastly larger numbers of electrons than from the emitter if for a given application the number of electrons is a crucial figure of merit. We believe that our straightforward and flexible design will be of great practical relevance to researchers wishing to enter the field.
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