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Ptychographic electron microscopy using high-angle dark-field scattering for sub-nanometre resolution imaging.

Humphry MJ, Kraus B, Hurst AC, Maiden AM, Rodenburg JM - Nat Commun (2012)

Bottom Line: Diffractive imaging, in which image-forming optics are replaced by an inverse computation using scattered intensity data, could, in principle, realize wavelength-scale resolution in a transmission electron microscope.However, to date all implementations of this approach have suffered from various experimental restrictions.Here we demonstrate a form of diffractive imaging that unshackles the image formation process from the constraints of electron optics, improving resolution over that of the lens used by a factor of five and showing for the first time that it is possible to recover the complex exit wave (in modulus and phase) at atomic resolution, over an unlimited field of view, using low-energy (30 keV) electrons.

View Article: PubMed Central - PubMed

Affiliation: Phase Focus Ltd, The Electric Works, Sheffield Digital Campus, Sheffield S1 2BJ, UK.

ABSTRACT
Diffractive imaging, in which image-forming optics are replaced by an inverse computation using scattered intensity data, could, in principle, realize wavelength-scale resolution in a transmission electron microscope. However, to date all implementations of this approach have suffered from various experimental restrictions. Here we demonstrate a form of diffractive imaging that unshackles the image formation process from the constraints of electron optics, improving resolution over that of the lens used by a factor of five and showing for the first time that it is possible to recover the complex exit wave (in modulus and phase) at atomic resolution, over an unlimited field of view, using low-energy (30 keV) electrons. Our method, called electron ptychography, has no fundamental experimental boundaries: further development of this proof-of-principle could revolutionize sub-atomic scale transmission imaging.

No MeSH data available.


Related in: MedlinePlus

Examples of the recorded diffraction patterns.(a) Free-space diffraction pattern, that is, collected when the probe is in free space. The disk is a shadow image cast by the condenser aperture. (b) Diffraction pattern from the sample. The strong bright-field intensity is seen inside the central disk, also known as the Gabor hologram or Ronchigram. (c) The same diffraction pattern as shown in b plotted on a log-intensity scale to show dark-field intensity data: the high-resolution information arises from this data. Scale bar, 1 nm−1. The ring indicates a radius of 0.236 nm−1.
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f2: Examples of the recorded diffraction patterns.(a) Free-space diffraction pattern, that is, collected when the probe is in free space. The disk is a shadow image cast by the condenser aperture. (b) Diffraction pattern from the sample. The strong bright-field intensity is seen inside the central disk, also known as the Gabor hologram or Ronchigram. (c) The same diffraction pattern as shown in b plotted on a log-intensity scale to show dark-field intensity data: the high-resolution information arises from this data. Scale bar, 1 nm−1. The ring indicates a radius of 0.236 nm−1.

Mentions: The main modification we have made to the microscope is that a CCD detector is positioned at the bottom of the specimen chamber. The CCD records the diffraction pattern, as exemplified by Fig. 2; in the centre of the pattern is a bright disk, which is a shadow image cast by the condenser aperture, and which is of the form of a Gabor hologram35 (otherwise known in the STEM literature as a Ronchigram'). Within this, diffracted amplitude interferes with a relative strong unscattered beam. Outside the central disk, we have so-called dark-field diffracted intensity.


Ptychographic electron microscopy using high-angle dark-field scattering for sub-nanometre resolution imaging.

Humphry MJ, Kraus B, Hurst AC, Maiden AM, Rodenburg JM - Nat Commun (2012)

Examples of the recorded diffraction patterns.(a) Free-space diffraction pattern, that is, collected when the probe is in free space. The disk is a shadow image cast by the condenser aperture. (b) Diffraction pattern from the sample. The strong bright-field intensity is seen inside the central disk, also known as the Gabor hologram or Ronchigram. (c) The same diffraction pattern as shown in b plotted on a log-intensity scale to show dark-field intensity data: the high-resolution information arises from this data. Scale bar, 1 nm−1. The ring indicates a radius of 0.236 nm−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3316878&req=5

f2: Examples of the recorded diffraction patterns.(a) Free-space diffraction pattern, that is, collected when the probe is in free space. The disk is a shadow image cast by the condenser aperture. (b) Diffraction pattern from the sample. The strong bright-field intensity is seen inside the central disk, also known as the Gabor hologram or Ronchigram. (c) The same diffraction pattern as shown in b plotted on a log-intensity scale to show dark-field intensity data: the high-resolution information arises from this data. Scale bar, 1 nm−1. The ring indicates a radius of 0.236 nm−1.
Mentions: The main modification we have made to the microscope is that a CCD detector is positioned at the bottom of the specimen chamber. The CCD records the diffraction pattern, as exemplified by Fig. 2; in the centre of the pattern is a bright disk, which is a shadow image cast by the condenser aperture, and which is of the form of a Gabor hologram35 (otherwise known in the STEM literature as a Ronchigram'). Within this, diffracted amplitude interferes with a relative strong unscattered beam. Outside the central disk, we have so-called dark-field diffracted intensity.

Bottom Line: Diffractive imaging, in which image-forming optics are replaced by an inverse computation using scattered intensity data, could, in principle, realize wavelength-scale resolution in a transmission electron microscope.However, to date all implementations of this approach have suffered from various experimental restrictions.Here we demonstrate a form of diffractive imaging that unshackles the image formation process from the constraints of electron optics, improving resolution over that of the lens used by a factor of five and showing for the first time that it is possible to recover the complex exit wave (in modulus and phase) at atomic resolution, over an unlimited field of view, using low-energy (30 keV) electrons.

View Article: PubMed Central - PubMed

Affiliation: Phase Focus Ltd, The Electric Works, Sheffield Digital Campus, Sheffield S1 2BJ, UK.

ABSTRACT
Diffractive imaging, in which image-forming optics are replaced by an inverse computation using scattered intensity data, could, in principle, realize wavelength-scale resolution in a transmission electron microscope. However, to date all implementations of this approach have suffered from various experimental restrictions. Here we demonstrate a form of diffractive imaging that unshackles the image formation process from the constraints of electron optics, improving resolution over that of the lens used by a factor of five and showing for the first time that it is possible to recover the complex exit wave (in modulus and phase) at atomic resolution, over an unlimited field of view, using low-energy (30 keV) electrons. Our method, called electron ptychography, has no fundamental experimental boundaries: further development of this proof-of-principle could revolutionize sub-atomic scale transmission imaging.

No MeSH data available.


Related in: MedlinePlus