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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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Nanosecond electron holography by interference gating. Ultramicroscopy 2019; 206:112824. [PMID: 31401353 DOI: 10.1016/j.ultramic.2019.112824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/19/2019] [Accepted: 07/26/2019] [Indexed: 11/24/2022]
Abstract
The interference gating is a novel method for robust time-resolved electron holographic measurements by directly switching the interference. Here, a new arrangement is presented in which a biprism in the condenser aperture as a fast electric phase shifter is used to control the interference pattern. High-frequency stimulation of the electric phase shifter in the gigahertz range are performed and observed via electron holography, proving the feasibility of interference gating in the upper picosecond range. Despite the bandwidth limitation of 180 MHz of the current signal generator, a time resolution of 100 ns is achieved through forward correction of the control signal. With this time resolution, it is already possible to measure the transient response of the biasing holder system. Our method paves the way towards a closer look on fast dynamic processes with high temporal and spatial resolution.
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Madan I, Vanacore GM, Pomarico E, Berruto G, Lamb RJ, McGrouther D, Lummen TTA, Latychevskaia T, García de Abajo FJ, Carbone F. Holographic imaging of electromagnetic fields via electron-light quantum interference. SCIENCE ADVANCES 2019; 5:eaav8358. [PMID: 31058225 PMCID: PMC6499551 DOI: 10.1126/sciadv.aav8358] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/15/2019] [Indexed: 05/22/2023]
Abstract
Holography relies on the interference between a known reference and a signal of interest to reconstruct both the amplitude and the phase of that signal. With electrons, the extension of holography to the ultrafast time domain remains a challenge, although it would yield the highest possible combined spatiotemporal resolution. Here, we show that holograms of local electromagnetic fields can be obtained with combined attosecond/nanometer resolution in an ultrafast transmission electron microscope (UEM). Unlike conventional holography, where signal and reference are spatially separated and then recombined to interfere, our method relies on electromagnetic fields to split an electron wave function in a quantum coherent superposition of different energy states. In the image plane, spatial modulation of the electron energy distribution reflects the phase relation between reference and signal fields. Beyond imaging applications, this approach allows implementing quantum measurements in parallel, providing an efficient and versatile tool for electron quantum optics.
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Affiliation(s)
- I. Madan
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
| | - G. M. Vanacore
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
| | - E. Pomarico
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
| | - G. Berruto
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
| | - R. J. Lamb
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - D. McGrouther
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - T. T. A. Lummen
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
| | - T. Latychevskaia
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
| | - F. J. 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
| | - F. Carbone
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland
- Corresponding author.
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