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Khaliq MW, Álvarez JM, Camps A, González N, Ferrer J, Martinez-Carboneres A, Prat J, Ruiz-Gómez S, Niño MA, Macià F, Aballe L, Foerster M. GHz sample excitation at the ALBA-PEEM. Ultramicroscopy 2023; 250:113757. [PMID: 37207610 DOI: 10.1016/j.ultramic.2023.113757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/14/2023] [Accepted: 05/08/2023] [Indexed: 05/21/2023]
Abstract
We describe a setup that is used for high-frequency electrical sample excitation in a cathode lens electron microscope with the sample stage at high voltage as used in many synchrotron light sources. Electrical signals are transmitted by dedicated high-frequency components to the printed circuit board supporting the sample. Sub-miniature push-on connectors (SMP) are used to realize the connection in the ultra-high vacuum chamber, bypassing the standard feedthrough. A bandwidth up to 4 GHz with -6 dB attenuation was measured at the sample position, which allows to apply sub-nanosecond pulses. We describe different electronic sample excitation schemes and demonstrate a spatial resolution of 56 nm employing the new setup.
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Affiliation(s)
- Muhammad Waqas Khaliq
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain; Department of Condensed Matter Physics, University of Barcelona, Barcelona, 08028 Spain.
| | - José M Álvarez
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | - Antonio Camps
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | - Nahikari González
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | - José Ferrer
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | | | - Jordi Prat
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | - Sandra Ruiz-Gómez
- Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden, Germany
| | - Miguel Angel Niño
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | - Ferran Macià
- Department of Condensed Matter Physics, University of Barcelona, Barcelona, 08028 Spain; Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, 08028 Barcelona, Spain
| | - Lucia Aballe
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, Carrer de la Llum, 2 - 26, Cerdanyola del Vallés, 08290 Barcelona, Spain.
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Dąbrowski M, Dai Y, Petek H. Ultrafast Microscopy: Imaging Light with Photoelectrons on the Nano-Femto Scale. J Phys Chem Lett 2017; 8:4446-4455. [PMID: 28853892 DOI: 10.1021/acs.jpclett.7b00904] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Experimental methods for ultrafast microscopy are advancing rapidly. Promising methods combine ultrafast laser excitation with electron-based imaging or rely on super-resolution optical techniques to enable probing of matter on the nano-femto scale. Among several actively developed methods, ultrafast time-resolved photoemission electron microscopy provides several advantages, among which the foremost are that time resolution is limited only by the laser source and it is immediately capable of probing of coherent phenomena in solid-state materials and surfaces. Here we present recent progress in interference imaging of plasmonic phenomena in metal nanostructures enabled by combining a broadly tunable femtosecond laser excitation source with a low-energy electron microscope.
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Affiliation(s)
- Maciej Dąbrowski
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Yanan Dai
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Hrvoje Petek
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
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Schönhense G, Medjanik K, Tusche C, de Loos M, van der Geer B, Scholz M, Hieke F, Gerken N, Kirschner J, Wurth W. Correction of the deterministic part of space-charge interaction in momentum microscopy of charged particles. Ultramicroscopy 2015; 159 Pt 3:488-96. [PMID: 26051657 DOI: 10.1016/j.ultramic.2015.05.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 05/13/2015] [Accepted: 05/15/2015] [Indexed: 10/23/2022]
Abstract
Ultrahigh spectral brightness femtosecond XUV and X-ray sources like free electron lasers (FEL) and table-top high harmonics sources (HHG) offer fascinating experimental possibilities for analysis of transient states and ultrafast electron dynamics. For electron spectroscopy experiments using illumination from such sources, the ultrashort high-charge electron bunches experience strong space-charge interactions. The Coulomb interactions between emitted electrons results in large energy shifts and severe broadening of photoemission signals. We propose a method for a substantial reduction of the effect by exploiting the deterministic nature of space-charge interaction. The interaction of a given electron with the average charge density of all surrounding electrons leads to a rotation of the electron distribution in 6D phase space. Momentum microscopy gives direct access to the three momentum coordinates, opening a path for a correction of an essential part of space-charge interaction. In a first experiment with a time-of-flight momentum microscope using synchrotron radiation at BESSY, the rotation in phase space became directly visible. In a separate experiment conducted at FLASH (DESY), the energy shift and broadening of the photoemission signals were quantified. Finally, simulations of a realistic photoemission experiment including space-charge interaction reveals that a gain of an order of magnitude in resolution is possible using the correction technique presented here.
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Affiliation(s)
- G Schönhense
- Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz, Germany.
| | - K Medjanik
- Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - C Tusche
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - M de Loos
- Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven, The Netherlands
| | - B van der Geer
- Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven, The Netherlands
| | - M Scholz
- Physics Department and Center for Free-Electron Laser Science, Univ. Hamburg, 22761 Hamburg, Germany
| | - F Hieke
- Physics Department and Center for Free-Electron Laser Science, Univ. Hamburg, 22761 Hamburg, Germany
| | - N Gerken
- Physics Department and Center for Free-Electron Laser Science, Univ. Hamburg, 22761 Hamburg, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - W Wurth
- Physics Department and Center for Free-Electron Laser Science, Univ. Hamburg, 22761 Hamburg, Germany; DESY Photon Science, 22607 Hamburg, Germany
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Fazekas Á, Tóth L. Filtering chromatic aberration for wide acceptance angle electrostatic lenses. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2014; 23:2834-2841. [PMID: 24808408 DOI: 10.1109/tip.2014.2321493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Chromatic aberration is a major issue for imaging mainly with large acceptance angle electrostatic lenses. Its correction is necessary to take advantage of the outstanding spatial and angular resolution that these lenses provide. We propose a method to eliminate the effect of chromatic aberration on the measured images by determining the impact resulting from higher and lower kinetic energies. Based on a spectral image sequence and a matrix, which describes the transmission function of the lens, a system of linear equations is solved to approximate the 2D spectral intensity distribution of the sample surface. We present the description of our method and preliminary test results, which show significant contrast and image quality improvement. The presented algorithm can also be applied as a software-based energy analyzer.
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Nickel F, Gottlob D, Krug I, Doganay H, Cramm S, Kaiser A, Lin G, Makarov D, Schmidt O, Schneider C. Time-resolved magnetic imaging in an aberration-corrected, energy-filtered photoemission electron microscope. Ultramicroscopy 2013; 130:54-62. [DOI: 10.1016/j.ultramic.2013.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/06/2013] [Accepted: 03/08/2013] [Indexed: 11/16/2022]
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Schertz F, Schmelzeisen M, Kreiter M, Elmers HJ, Schönhense G. Field emission of electrons generated by the near field of strongly coupled plasmons. PHYSICAL REVIEW LETTERS 2012; 108:237602. [PMID: 23003989 DOI: 10.1103/physrevlett.108.237602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Indexed: 06/01/2023]
Abstract
Field emission of electrons is generated solely by the ultrastrong near-field of strongly coupled plasmons without the help of a noticeable dc field. Strongly coupled plasmons are excited at Au nanoparticles in subnanometer distance to a Au film by femtosecond laser pulses. Field-emitted electrons from individual nanoparticles are detected by means of photoelectron emission microscopy and spectroscopy. The dependence of total electron yield and kinetic energy on the laser power proves that field emission is the underlying emission process. We derive a dynamic version of the Fowler-Nordheim equation that yields perfect agreement with the experiment.
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Affiliation(s)
- Florian Schertz
- Institut für Physik, Universität Mainz, Staudinger Weg 7, D-55099 Mainz, Germany.
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Schneider C, Krug I, Müller M, Matthes F, Kaiser A, Wiemann C, Cramm S, Elmers HJ, Wegelin F, Krasyuk A, Nepijko S, Schönhense G. Investigating spintronics thin film systems with synchrotron radiation. Radiat Phys Chem Oxf Engl 1993 2009. [DOI: 10.1016/j.radphyschem.2009.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Kaiser A, Wiemann C, Cramm S, Schneider CM. Influence of magnetocrystalline anisotropy on the magnetization dynamics of magnetic microstructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:314008. [PMID: 21828569 DOI: 10.1088/0953-8984/21/31/314008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The study of magnetodynamics using stroboscopic time-resolved x-ray photoemission electron microscopy (TR-XPEEM) involves an intrinsic timescale provided by the pulse structure of the synchrotron radiation. In the usual multi-bunch operation mode, the time span between two subsequent light pulses is too short to allow a relaxation of the system into the ground state before the next pump-probe cycle starts. Using a deflection gating mechanism described in this paper we are able to pick the photoemission signal resulting from selected light pulses. Thus, PEEM measurements can be carried out in a flexible timing scheme with longer delays between two light pulses. Using this technique, the magnetodynamics of both Permalloy and iron structures have been investigated. The differences in the dynamic response on a short magnetic field pulse are discussed with respect to the magnetocrystalline anisotropy.
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Affiliation(s)
- A Kaiser
- Forschungszentrum Jülich, Institut für Festkörperforschung IFF-9, and JARA-FIT, 52425 Jülich, Germany
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Bauer E. Cathode lens electron microscopy: past and future. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:314001. [PMID: 21828562 DOI: 10.1088/0953-8984/21/31/314001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This retrospective sketches the evolution of emission electron microscopy, low energy electron microscopy and related methods from the early stages up to the present state and gives a brief outlook on the future possibilities of these cathode lens electron microscopy techniques. It is concerned mainly with instrumentation, discusses some little known work and emphasizes important steps in the evolution of the field instead of attempting to review it in detail.
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Affiliation(s)
- E Bauer
- Department of Physics, Arizona State University, Tempe, AZ 85287-1504, USA
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Howie A. Photon-assisted electron energy loss spectroscopy and ultrafast imaging. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2009; 15:314-322. [PMID: 19575832 DOI: 10.1017/s1431927609090254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A variety of ways is described in which photons can be used not only for ultrafast electron microscopy but also to enormously widen the energy range of spatially-resolved electron spectroscopy. Periodic chains of femtosecond laser pulses are a particularly important and accurately timed source for single-shot imaging and diffraction as well as for several forms of pump-probe microscopy at even higher spatial resolution and sub-picosecond timing. Many exciting new fields are opened up for study by these developments. Ultrafast, single shot diffraction with intense pulses of X-rays supplemented by phase retrieval techniques may eventually offer a challenging alternative and purely photon-based route to dynamic imaging at high spatial resolution.
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Affiliation(s)
- Archie Howie
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK.
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