EMC Abstracts

Official abstracts site for the European Microscopy Congress

MENU 
  • Home
  • Meetings Archive
    • The 16th European Microscopy Congress 2016
  • Keyword Index
  • Your Favorites
    • Favorites
    • Login
    • Register
    • View and Print All Favorites
    • Clear all your favorites
  • Advanced Search

Double crystal interference experiments

Abstract number: 5140

Session Code: IM07-364

DOI: 10.1002/9783527808465.EMC2016.5140

Meeting: The 16th European Microscopy Congress 2016

Session: Instrumentation and Methods

Topic: Phase Microscopies

Presentation Form: Poster

Corresponding Email: martial.duchamp@gmail.com

Amir H. Tavabi (1), Martial Duchamp (1), Rafal E. Dunin-Borkowski (1), Giulio Pozzi (1, 2)

1. The Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, Jülich, Allemagne 2. Department of Physics and Astronomy, University of Bologna, Bologna, Italie

Keywords: electron diffraction, electron interference

In 1978, Rackham and co-workers observed remarkable and unusual diffraction patterns from an object that consisted of two perfectly aligned, simultaneously reflecting crystals that were separated by a gap [1]. They reported that they could obtain such double crystals routinely by ion bombardment. However, their specimen preparation method did not allow the the gap between the crystals to be controlled and the maximum gap that they achieved was on the order of 1-2 μm. A subsequent realization of a double crystal interferometer (DCI) was achieved using voids in spinel [2], again with a crystal spacing of below 1 μm. In 1995, Zhou and co-workers [3] presented new results by combining a Si double-crystal interferometer with convergent beam electron diffraction (CBED), taking advantage of a special structure formed at the broken edge of a Si [111] crystal. The gap was still on the order of 1 μm or below.

.

Here, we use focused ion beam (FIB) milling to build DCIs that have gaps of up to 8 μm and to provide better control over results that were previously obtained by chance. Figure 1 shows a top view scanning electron micrograph of such an interferometer. The gap separation is 800 nm. Both single crystal and double crystal areas have been patterned. Superimposed on the image is a sketch of the ray path of a convergent beam that illuminates the upper crystal, generating a transmitted beam and a diffracted beam. These beams, in turn, impinge on the second crystal, generating further transmitted and diffracted beams that overlap in the diffraction plane, resulting in the formation of interference fringes.

.

Figure 2 shows a comparison of diffraction patterns recorded from a single crystal (left) and two overlapped crystals (right). The spacing of the interference fringes depends on the electron wavelength, the excited Bragg reflection and the camera length. More impressive results are obtained when the orientation of the crystal is close to a zone axis. Figure 3 shows a comparison of a standard CBED pattern (left) with a complicated system of interference fringes arising from overlap of many diffracted beams (right). The interference phenomena in these patterns encode information about the crystal structure. The fringe spacing is inversely propotional to the gap width. Therefore, for an 8 μm gap, ten times more fringes are present in the overlapped discs and the interferogram can be considered as a hologram, as showsn in Fig. 4.

.

As suggested by the first experimenters [1], accurate lattice parameter measurements can be made using a DCI when one crystal is the specimen of interest. If, instead, a specimen in inserted between the crystals or deposited onto the lower crystal, then it will be possible to obtain an off-axis Fresnel hologram with a reduced exposure time that is not affected by Fresnel

diffraction from the edges of a biprism wire, as is the case when an electron biprism is used as an interferometric device. Moreover, the reduced exposure time due to amplitude division beam splitting could open the way to dynamic recording and processing of holograms.

.

[1] G.M. Rackham, J.E. Loveluck and J.W. Steeds. Journal of Physics: Conference Series, 41 (1977) 435.

[2] C.B. DeCooman and C.B. Carter. Ultramicroscopy, 13 (1984) 233.

[3] F. Zhou, E. Plies and G. Möllenstedt. Optik,98 (1995) 95.

.

We acknowledge financial support from the European Union under the Seventh Framework Programme under a contract for an Integrated Infrastructure Initiative (Reference 312483 ESTEEM2) and the European Research Council for an Advanced Grant (Reference 320832 IMAGINE).

Figures:

Figure 1: Secondary electron image of two crystalline Si slabs, with schematic ray paths superimposed for a two beam condition. The scale bar is 1 µm.

Figure 2: Single crystal (left) and double crystal (right) CBED patterns recorded from Si, showing interference fringes in the double crystal pattern.

Figure 3: Single crystal (left) and double crystal (right) CBED patterns recorded from Si, showing interference fringes in the double crystal pattern due to overlapping diffracted discs in a near-zone-axis orientation.

Figure 4: CBED pattern recorded from a double crystal of Si with a gap of 8 μm. The inset shows the interference fringes at higher magnification.

To cite this abstract:

Amir H. Tavabi, Martial Duchamp, Rafal E. Dunin-Borkowski, Giulio Pozzi; Double crystal interference experiments. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/double-crystal-interference-experiments/. Accessed: December 14, 2019
  • Tweet
  • Email
  • Print
Save to PDF

« Back to The 16th European Microscopy Congress 2016

EMC Abstracts - https://emc-proceedings.com/abstract/double-crystal-interference-experiments/

Most Viewed Abstracts

  • mScarlet, a novel high quantum yield (71%) monomeric red fluorescent protein with enhanced properties for FRET- and super resolution microscopy
  • 3D structure and chemical composition reconstructed simultaneously from HAADF-STEM images and EDS-STEM maps
  • Pixelated STEM detectors: opportunities and challenges
  • Layer specific optical band gap measurement at nanoscale in MoS2 and ReS2 van der Waals compounds by high resolution electron energy loss spectroscopy
  • Crystallographic mapping in engineering alloys by scanning precession electron diffraction

Your Favorites

You can save and print a list of your favorite abstracts by clicking the “Favorite” button at the bottom of any abstract. View your favorites »

Visit Our Partner Sites

The 16th European Microscopy Congress

The official web site of the 16th European Microscopy Congress.

European Microscopy Society

European Microscopy Society logoThe European Microscopy Society (EMS) is committed to promoting the use and the quality of advanced microscopy in all its aspects in Europe.

International Federation of Societies for Microscopy

International Federation of Societies for Microscopy logoThe IFSM aims to contribute to the advancement of microscopy in all its aspects.

Société Française des Microscopies

Société Française des MicroscopiesThe Sfµ is a multidisciplinary society which aims to improve and spread the knowledge about Microscopy.

Connect with us

Imaging & Microscopy
Official Media Partner of the European Microscopy Society.

  • Help & Support
  • About Us
  • Cookies & Privacy
  • Wiley Job Network
  • Terms & Conditions
  • Advertisers & Agents
Copyright © 2019 John Wiley & Sons, Inc. All Rights Reserved.
Wiley
loading Cancel
Post was not sent - check your email addresses!
Email check failed, please try again
Sorry, your blog cannot share posts by email.
This site uses cookies: Find out more.