Tutorial on Off-Axis Electron Holography

2002 ◽  
Vol 8 (6) ◽  
pp. 447-466 ◽  
Author(s):  
Michael Lehmann ◽  
Hannes Lichte
Keyword(s):  
Materials Science ◽  
Electron Holography ◽  
Large Area ◽  
Transmission Electron ◽  
Step Procedure ◽  
Medium Resolution ◽  
Wide Range ◽  
Electric Potentials ◽  
Electron Microscopes ◽  
Powerful Electron

Through recent years, off-axis electron holography has helped us to understand and to overcome some experimental restrictions in transmission electron microscopy. With development of powerful electron microscopes, slow-scan CCD cameras, and computers, holography is not an academic technique anymore used by specialized laboratories. Holography has proven its wide range of applications in solving real-world problems in materials science and biology. At medium resolution, that is, on nanometer scale, holography allows access to large area phase contrast produced by magnetic fields and electric potentials. In the high-resolution domain, holography unveils its power by unscrambling amplitude and phase of the electron wave, resulting in an improved lateral resolution up to the information limit. Holography is a thoroughly quantitative method, and, in combination with the perfect zero-loss filtering inherent to this method, the interpretation of the reconstructed data is strongly simplified. After outlining the basics of holography, in this tutorial we focus on development of a step-by-step procedure for recording and reconstruction of holograms. At the end, some recent applications are discussed.

SHaRE: Collaborative materials science research

1988 ◽  
Vol 46 ◽  
pp. 804-805
Author(s):  
Edward A. Kenik ◽  
Karren L. More
Keyword(s):  
Electron Microscope ◽  
Materials Science ◽  
Analytical Electron Microscopy ◽  
Science Research ◽  
Atom Probe ◽  
Probe Field ◽  
Transmission Electron ◽  
Wide Range ◽  
Analytical Electron ◽  
Electron Microscopes

The Shared Research Equipment (SHaRE) Program provides access to the wide range of advanced equipment and techniques available in the Metals and Ceramics Division of ORNL to researchers from universities, industry, and other national laboratories. All SHaRE projects are collaborative in nature and address materials science problems in areas of mutual interest to the internal and external collaborators. While all facilities in the Metals and Ceramics Division are available under SHaRE, there is a strong emphasis on analytical electron microscopy (AEM), based on state-of-the-art facilities, techniques, and recognized expertise in the Division. The microscopy facilities include four analytical electron microscopes (one 300 kV, one 200 kV, and two 120 kV instruments), a conventional transmission electron microscope with a low field polepiece for examination of ferromagnetic materials, a high voltage (1 MV) electron microscope with a number of in situ capabilities, and a variety of EM support facilities. An atom probe field-ion microscope provides microstructural and elemental characterization at atomic resolution.

Instrumentation and Computation

1990 ◽  
Vol 48 (1) ◽  
pp. 2-3
Author(s):  
P.B. Hirsch
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Materials Science ◽  
Image Interpretation ◽  
Specimen Preparation ◽  
Scanning Tunnelling Microscope ◽  
Transmission Electron ◽  
Wide Range ◽  
Electron Microscopes ◽  
Types Of Information

The benefit to society arising from developments in instrumentation and computation can be judged primarily by the advances in knowledge and understanding generated by their application in different branches of science, covered in the other papers in this symposium. Without advances in instrumentation none of these advances is possible; developments in instrumentation and in image interpretation are therefore fundamental to and precede scientific advances in fields in which knowledge of structure is important. There is little doubt that the revolutionary first step was the development of the transmission electron microscope (TEM) in 1931 by Ernst Ruska; a second was the development of the scanning electron microscope (SEM); and the third the introduction of the scanning tunnelling microscope (STM) for high resolution surface imaging, by Binnig and Rohrer.The TEM and SEM have undergone continuous developments over the last 50 years or so, and have had a far-reaching impact in a wide range of disciplines; the STM is a relative newcomer but no doubt it too will have an increasing impact in furthering our understanding of solids and surfaces in particular. Once the basic instruments became available subsequent developments have been driven by the demands of the scientific disciplines in which these instruments have been applied. Many of the new developments in instrumentation and interpretation have been pioneered by the users themselves, and these in turn have led to modifications in commercial instruments to make such advances in technique available to the user community as a whole. Other developments have been initiated directly by the manufacturers as a result of a perceived need. There has been and continues to be a close interaction between the developers of hardware (not only of electron microscopes but also of ancillary equipment, e.g. microanalysis attachments, image processing equipment, specialist specimen stages, and specimen preparation facilities) and the users, leading to extensions in the range of applications and the types of information which can be obtained by electron microscopy. The following examples from the developments of electron microscopy in Materials Science illustrate these interactions and the particular advances arising from specific developments:

Electron holography in materials science

1991 ◽  
Vol 49 ◽  
pp. 670-671
Author(s):  
Hannes Lichte ◽  
Edgar Voelkl
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Fourier Spectrum ◽  
Object Wave ◽  
Electron Holography ◽  
Reconstruction Procedure ◽  
Numerical Reconstruction ◽  
Transmission Electron ◽  
Unique Interpretation

The object wave o(x,y) = a(x,y)exp(iφ(x,y)) at the exit face of the specimen is described by two real functions, i.e. amplitude a(x,y) and phase φ(x,y). In stead of o(x,y), however, in conventional transmission electron microscopy one records only the real intensity I(x,y) of the image wave b(x,y) loosing the image phase. In addition, referred to the object wave, b(x,y) is heavily distorted by the aberrations of the microscope giving rise to loss of resolution. Dealing with strong objects, a unique interpretation of the micrograph in terms of amplitude and phase of the object is not possible. According to Gabor, holography helps in that it records the image wave completely by both amplitude and phase. Subsequently, by means of a numerical reconstruction procedure, b(x,y) is deconvoluted from aberrations to retrieve o(x,y). Likewise, the Fourier spectrum of the object wave is at hand. Without the restrictions sketched above, the investigation of the object can be performed by different reconstruction procedures on one hologram. The holograms were taken by means of a Philips EM420-FEG with an electron biprism at 100 kV.

Remote On-Line Control of a High-Voltage in situ Transmission Electron Microscope with A Rational User Interface

1996 ◽  
Vol 54 ◽  
pp. 384-385
Author(s):  
M.A. O’Keefe ◽  
J. Taylor ◽  
D. Owen ◽  
B. Crowley ◽  
K.H. Westmacott ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
User Interface ◽  
Transmission Electron Microscope ◽  
High Voltage ◽  
Materials Science ◽  
Transmission Electron ◽  
On Line ◽  
Electron Microscopes

Remote on-line electron microscopy is rapidly becoming more available as improvements continue to be developed in the software and hardware of interfaces and networks. Scanning electron microscopes have been driven remotely across both wide and local area networks. Initial implementations with transmission electron microscopes have targeted unique facilities like an advanced analytical electron microscope, a biological 3-D IVEM and a HVEM capable of in situ materials science applications. As implementations of on-line transmission electron microscopy become more widespread, it is essential that suitable standards be developed and followed. Two such standards have been proposed for a high-level protocol language for on-line access, and we have proposed a rational graphical user interface. The user interface we present here is based on experience gained with a full-function materials science application providing users of the National Center for Electron Microscopy with remote on-line access to a 1.5MeV Kratos EM-1500 in situ high-voltage transmission electron microscope via existing wide area networks. We have developed and implemented, and are continuing to refine, a set of tools, protocols, and interfaces to run the Kratos EM-1500 on-line for collaborative research. Computer tools for capturing and manipulating real-time video signals are integrated into a standardized user interface that may be used for remote access to any transmission electron microscope equipped with a suitable control computer.

Analysis of Interesting Materials in the Environmental SEM: You Put What in Your Microscope?

2001 ◽  
Vol 7 (S2) ◽  
pp. 776-777
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Microscope ◽  
Chemical Engineering ◽  
Materials Science ◽  
Variable Pressure ◽  
Environmental Scanning ◽  
Specimen Preparation ◽  
Wide Range ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM™) and variable pressure electron microscope (VPSEM) have become accepted tools in the contemporary electron microscopy facility. Their flexibility and their ability to image almost any sample with little, and often no, specimen preparation has proved so attractive that each manufacturer of scanning electron microscopes now markets a low vacuum model.The University of Michigan Electron Microbeam Analysis Laboratory (EMAL) operates two variable pressure instruments, an ElectroScan E3 ESEM and a Hitachi S3200N VPSEM. The E3 ESEM was acquired in the early 1990s with funding from the Amoco Foundation and it has been used to examine an extremely wide variety of different materials. Since EMAL serves the entire university community, and offers support to neighboring institutions and local industry, the types of materials examined span a wide range. There are users from Materials Science & Engineering, Chemical Engineering, Nuclear Engineering, Electrical Engineering, Physics, Chemistry, Geology, Biology, Biophysics, Pharmacy and Pharmacology.

scholarly journals Modern Microscopy on the Light Side: TEM in the Trenches

1993 ◽  
Vol 1 (4) ◽  
pp. 6-10
Author(s):  
Stephen E. Rice
Keyword(s):  
Science Fiction ◽  
Great Promise ◽  
Electron Holography ◽  
Imaging Device ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Light Side ◽  
Convergent Beam ◽  
Made In

Great strides have been made in the last decade in high resolution transmission electron microscopes (TEMs) which can also provide elemental information via energy dispersive X-ray analysis (EDX) or energy loss spectroscopy (EELS), and proponents of various TEM techniques make bold claims. Convergent beam elecjron diffraction and microdifff action shine as techniques for defect structure analysis and means for solving crystal structures. The spectroscopies can now be used to map chemical state information at a level which until recently might be encountered in science fiction. As a pure imaging device, electron holography holds great promise for providing Ehe ultimate (would you believe 0.1Å?) imaging resolution. Although conventional TEMs will never approach this, it appears that we are learning more and more about less and less, until we will soon know everything there is to know about nothing.

scholarly journals Atomically resolved tomographic reconstruction of nanoparticles from Single Projection: influence of amorphous carbon support

2020 ◽  
Author(s):  
Pritam Banerjee ◽  
Chiranjit Roy ◽  
Subhra Kanti De ◽  
Antonio J. Santos ◽  
Francisco M. Morales ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Tomographic Reconstruction ◽  
Carbon Film ◽  
Carbon Support ◽  
Atomic Scale ◽  
Structure Property ◽  
Transmission Electron ◽  
Wide Range ◽  
Correlation Information ◽  
Electron Microscopes

Abstract Nanoparticles have a wide range of applications due to their unique geometry and arrangement of atoms. For a precise structure-property correlation, information regarding atomically resolved 3D structures of nanoparticles is utmost beneficial. Though modern aberration-corrected transmission electron microscopes can resolve atoms with sub-angstrom resolution, an atomic-scale 3D reconstruction of nanoparticle is a challenge using tilt series tomography due to high radiation damage. Instead, inline 3D holography based tomographic reconstructions from single projection registered at low electron doses are more suitable for defining atoms dispositions at nanostructures. Nanoparticles are generally supported on amorphous carbon film for TEM experiments. However, neglecting the influence of carbon film on the tomographic reconstruction of the nanoparticle may lead to ambiguity. In order to address this issue, the effect of amorphous carbon support was quantitatively studied using simulations and experiments.

Is a TEM for “Real World” Application Available Presently?

2001 ◽  
Vol 7 (S2) ◽  
pp. 522-523
Author(s):  
W. Probst ◽  
G. Benner ◽  
B. Kabius ◽  
G. Lang ◽  
S. Hiller ◽  
...  
Keyword(s):  
Real World ◽  
Leading Edge ◽  
Ease Of Use ◽  
Real World Application ◽  
Transmission Electron ◽  
Wide Range ◽  
Race Horse ◽  
Electron Microscopes ◽  
Ray Path ◽  
Technological Opportunities

Transmission electron microscopes have been built along with and guided by technological opportunities since the last five decades. Even though there are some “workhorse” type of microscopes, these instruments are still more or less built from the technological viewpoint and less from the viewpoint of ease of use in a wide range of applications. On the other hand, leading edge applications are the drivers for the development and the use of leading edge technology. The result then is a “race horse” which is of very limited benefit in “Real world”.During the last decade computers have been integrated to build microscope systems. in most cases, however, computers still have to deal with obsolete electron optical ray path designs and thus, have to be used more to overcome the problems of imperfect optics and bad design of ray paths than to provide optimized “Real world” capabilities.

Three Dimensional Mask Metrology by Off-Axis Electron Holography

2001 ◽  
Vol 7 (S2) ◽  
pp. 574-575
Author(s):  
Bernhard Frost ◽  
David C Joy
Keyword(s):  
Three Dimensional ◽  
Ccd Camera ◽  
Electron Holography ◽  
Dimensional Metrology ◽  
Transmission Electron ◽  
Stereo Photogrammetry ◽  
Real Objects ◽  
Electron Microscopes ◽  
Third Dimension ◽  
Scanning Electron Microscopes

Even though all real objects are three dimensional, imaging and metrology performed by using electron-beam tools such as scanning electron microscopes is inherently two dimensional. Any information about the third dimension must therefore be obtained by inference, or by time consuming special methods such as stereo-photogrammetry. If, however, the structures of interest are thin enough to be electron transparent then quantitative three dimensional metrology can be performed directly by using off-axis transmission electron holography. Here we demonstrate the application to a SCALPEL lithography mask which consists of chromium lines on a silicon support film. The off-axis holography was performed in a field emission transmission electron microscope, a Hitachi HF2000 operated at 200keV. The sample is positioned so that half the beam passes through the specimen while the rest travels only through the vacuum. An electrostatic biprism then recombines these two components to form the hologram which is recorded onto a CCD camera.

High-performance EM-002B optical column construction for future expansion

1993 ◽  
Vol 51 ◽  
pp. 256-257
Author(s):  
K. Shirota ◽  
K. Moriyama ◽  
S. Mikami ◽  
A. Ando ◽  
O. Nakamura ◽  
...  
Keyword(s):  
High Performance ◽  
Cold Trap ◽  
Objective Lens ◽  
Transmission Electron ◽  
Probe Size ◽  
Wide Range ◽  
Electron Microscopes ◽  
Time Required ◽  
Modern Analytical ◽  
Typical User

Since modern analytical transmission electron microscopes must have a wide range of illumination conditions (from “mm” to “nm” probe size), an additional lens (one of the condenser lenses, usually called the “mini-lens”) is arranged immediately above the objective lens pole pieces. As a result, it has become very difficult to install an exchange mechanism for the objective pole pieces, which used to be done routinely.To overcome this, TOPCON Electron Microscope EM-OO2B incorporated a new mechanism which can be exchanged quite easily and reliably by the user. This mechanism makes a space to exchange pole pieces, without column disassembly, by precisely driven external mechanisms (Fig. 1). The time required for a typical user to carry out such exchange is usually 15 to 20 minutes, and it will take not more than two hours for high resolution image or analysis after exchange. This time is also shortened by the fact that an anti-contamination cold trap is not generally required in the case of EM-OO2B.

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