Related Experiment Video
Updated: Jul 9, 2026
08:04
Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography
Published on: March 12, 2017
Imaging modes for scanning confocal electron microscopy in a double aberration-corrected transmission electron
P D Nellist1, E C Cosgriff, G Behan
1Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK. peter.nellist@materials.ox.ac.uk
Summary
Aberration correction in electron microscopy enables optical sectioning for clearer imaging. Scanning confocal electron microscopy (SCEM) offers superior depth resolution compared to traditional methods.
Area of Science:
- Electron Microscopy
- Materials Science
- Nanotechnology
Background:
- Aberration correction in electron microscopes reduces the focal depth of field.
- This reduced depth of field enables optical sectioning to probe specific sample depths.
- Scanning transmission electron microscopy (STEM) utilizes optical sectioning for depth analysis.
Purpose of the Study:
- To survey coherent and incoherent imaging modes for scanning confocal electron microscopy (SCEM).
- To provide expressions describing SCEM imaging.
- To compare the depth response of SCEM with optical sectioning in STEM.
Main Methods:
- Utilizing an electron microscope with aberration correctors for pre- and post-specimen optics.
- Operating the microscope in a confocal mode (SCEM).
- Performing Bloch wave calculations for SCEM geometry with defocused optics.
Main Results:
- SCEM provides improved depth resolution and selectivity over optical sectioning in STEM.
- Calculations demonstrate the depth response of SCEM.
- Depth resolution in crystalline matrices was explored using Bloch wave calculations.
Conclusions:
- SCEM offers enhanced depth probing capabilities in electron microscopy.
- The developed imaging modes and calculations are crucial for SCEM applications.
- SCEM represents a significant advancement for high-resolution subsurface imaging.
Related Concept Videos
01:16Confocal Fluorescence Microscopy
Confocal microscopy is an advanced microscopic technique. The prime advantage of the confocal microscope over other microscopy techniques is its ability to block the out-of-focus light from the illuminated samples using pinholes. It is widely used with fluorescence optics to obtain high-resolution, sharp contrast images. Unlike optical microscopes, confocal microscopes use a focused beam of light laser to scan the entire sample surface at different z-planes. These microscopes are, therefore,...
01:25Overview of Electron Microscopy
The wavelengths of visible light ultimately limit the maximum theoretical resolution of images created by light microscopes. Most light microscopes can only magnify 1000X, and a few can magnify up to 1500X. Electrons, like electromagnetic radiation, can behave like waves, but with wavelengths of 0.005 nm, they produce significantly greater resolution up to 0.05 nm as compared to 500 nm for visible light. An electron microscope (EM) can create a sharp image that is magnified up to 2,000,000X.
01:37Super-resolution Fluorescence Microscopy
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been developed.
01:15Transmission Electron Microscopy
In 1931, physicist Ernst Ruska—building on the idea that magnetic fields can direct an electron beam just as lenses can direct a beam of light in an optical microscope—developed the first prototype of the electron microscope. This development led to the development of the field of electron microscopy. In the transmission electron microscope (TEM), electrons are produced by a hot tungsten element and accelerated by a potential difference in an electron gun, which gives them up to 400 keV in...
01:22Overview of Microscopy Techniques
The early pioneers of microscopy opened a window into the invisible world of microorganisms. In 1830, Joseph Jackson Lister created an essentially modern light microscope. The 20th century saw the development of microscopes that leveraged nonvisible light, such as fluorescence microscopy that uses an ultraviolet light source and electron microscopy that uses short-wavelength electron beams. These advances significantly improved magnification, image resolution, and contrast. By comparison, the...
01:07Electron Microscope Tomography and Single-particle Reconstruction
Transmission electron microscopy (TEM) can be used to determine the 3D structure of biological samples with the help of techniques such as electron microscope tomography and single-particle reconstruction. While single-particle reconstruction can examine macromolecules and macromolecular complexes in vitro conditions only, tomography permits the study of cell components or small cells in vivo.
Electron Tomography
Electron tomography can be performed either in TEM or STEM (scanning transmission...
Electron Tomography
Electron tomography can be performed either in TEM or STEM (scanning transmission...