Path-separated electron interferometry in a scanning transmission electron microscope

Yasin, Fehmi; Harvey, Tyler R.; Chess, Jordan; Pierce, Jordan; McMorran, Benjamin

doi:10.1088/1361-6463/aabc47

Cited by 21 publications

(27 citation statements)

References 41 publications

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“…In the setup we previously demonstrated [31], with a phase diffraction grating that produces three dominant beams, it is possible to image with the m = +1 beam, with the m =< 1 beams in vacuum for reference, and treat contributions from the much weaker m > 1 beams as noise. However, we expect that more efficient imaging is possible with an iterative reconstruction process.…”

Section: Appendix B: Aberrationsmentioning

confidence: 99%

Interpretable and Efficient Interferometric Contrast in Scanning Transmission Electron Microscopy with a Diffraction-Grating Beam Splitter

et al. 2018

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Efficient imaging of biomolecules, 2D materials and electromagnetic fields depends on retrieval of the phase of transmitted electrons. We demonstrate a method to measure phase in a scanning transmission electron microscope using a nanofabricated diffraction grating to produce multiple probe beams. The measured phase is more interpretable than phase-contrast scanning transmission electron microscopy techniques without an off-axis reference wave, and the resolution could surpass that of off-axis electron holography. We apply the technique to image nanoparticles, carbon substrates and electric fields. The contrast observed in experiments agrees well with contrast predicted in simulations.

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Section: Appendix B: Aberrationsmentioning

confidence: 99%

Interpretable and Efficient Interferometric Contrast in Scanning Transmission Electron Microscopy with a Diffraction-Grating Beam Splitter

et al. 2018

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“…The specimen transfer function contains an amplitude and phase, which can be used to calculate the thickness of a specimen. For a non-magnetic specimen, the phase imparted onto an electron wave-front is proportional to the electrostatic potential projected through the bulk of the specimen [14]. For amorphous materials, we may consider only the mean inner potential, V i .…”

Section: Phase-thickness Relationmentioning

confidence: 99%

Probing Light Atoms at Subnanometer Resolution: Realization of Scanning Transmission Electron Microscope Holography

et al. 2018

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Atomic resolution imaging in transmission electron microscopy (TEM) and scanning TEM (STEM) of light elements in electron-transparent materials has long been a challenge. Biomolecular materials, for example, are rapidly altered when illuminated with electrons. These issues have driven the development of TEM and STEM techniques that enable the structural analysis of electron beam-sensitive and weakly scattering nano-materials. Here, we demonstrate such a technique, STEM holography, capable of absolute phase and amplitude object wave measurement with respect to a vacuum reference wave. We use an amplitude-dividing nanofabricated grating to prepare multiple spatially separated electron diffraction probe beams focused at the sample plane, such that one beam transmits through the specimen while the others pass through vacuum. We raster-scan the diffracted probes over the region of interest. We configure the post-specimen imaging system of the microscope to diffraction mode, overlapping the probes to form an interference pattern at the detector. Using a fast-readout, direct electron detector, we record and analyze the interference fringes at each position in a 2D raster scan to reconstruct the complex transfer function of the specimen, t(x). We apply this technique to image a standard target specimen consisting of gold nanoparticles on a thin amorphous carbon substrate, and demonstrate 2.4Å resolution phase images. We find that STEM holography offers higher phase-contrast of the amorphous material while maintaining Au atomic lattice resolution when compared with high angle annular dark field STEM.

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“…With recent progress in nanofabrication, it has become possible to perform amplitude-division interferometry with a Mach-Zehnder interferometer in a standard transmission electron microscope (TEM) [30,31] and scanning transmission electron microscope (STEM) [32]. TEMs provide the advantage of a high-brightness electron beam that is easy to manipulate.…”

Section: Introductionmentioning

confidence: 99%

Reduced damage in electron microscopy by using interaction-free measurement and conditional reillumination

et al. 2019

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Interaction-free measurement (IFM) has been proposed as a means of high-resolution, low-damage imaging of radiation-sensitive samples, such as biomolecules and proteins. The basic setup for IFM is a Mach-Zehnder interferometer, and recent progress in nanofabricated electron diffraction gratings has made it possible to incorporate a Mach-Zehnder interferometer in a transmission-electron microscope (TEM). Therefore, the limits of performance of IFM with such an interferometer and a shot-noise limited electron source (such as that in a TEM) are of interest. In this work, we compared the error probability and sample damage for ideal IFM and classical imaging schemes, through theoretical analysis and numerical simulation. We considered a sample that is either completely transparent or completely opaque at each pixel. In our analysis, we also evaluated the impact of an additional detector for scattered electrons. The additional detector resulted in reduction of error by up to an order of magnitude, for both IFM and classical schemes. We also investigated a sample re-illumination scheme based on updating priors after each round of illumination and found that this scheme further reduced error by a factor of two. Implementation of these methods is likely achievable with existing instrumentation and would result in improved resolution in low-dose electron microscopy.

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Path-separated electron interferometry in a scanning transmission electron microscope

Cited by 21 publications

References 41 publications

Interpretable and Efficient Interferometric Contrast in Scanning Transmission Electron Microscopy with a Diffraction-Grating Beam Splitter

Interpretable and Efficient Interferometric Contrast in Scanning Transmission Electron Microscopy with a Diffraction-Grating Beam Splitter

Probing Light Atoms at Subnanometer Resolution: Realization of Scanning Transmission Electron Microscope Holography

Reduced damage in electron microscopy by using interaction-free measurement and conditional reillumination

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