Electron holography on Fraunhofer diffraction

Shimada

Ono

2020

Appl. Phys. Express

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A combined technology of vortex beam technique and electron holography has been developed. A range about 10 times the diameter of the grating opening was irradiated and two-wave interference between a Bragg diffraction wave as a vortex beam and a transmitted wave from and around a fork-shaped grating was recorded as a hologram. Reconstruction by using the Fourier transform method was simultaneously performed for amplitude and phase distributions. Furthermore, by using a wave aberration function, the amplitude and phase distributions at various propagation positions were reconstructed numerically, resulting in the confirmation of vortex beam twists.

mentioning

confidence: 99%

Electron holography for vortex beams

Shimada

Ono

2020

Appl. Phys. Express

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“…These methods are effective for a large propagation distance between the spatial position for the target object and the position for recording hologram [ 77–80 ]. It is particularly effective for the electron holography when small-angle electron diffractions [ 81 ] are involved, for example, observations of vortex beams [ 82 ], magnetic materials and diffraction waves.…”

Section: Electron Interference Optical Systemsmentioning

confidence: 99%

Interference and interferometry in electron holography

2020

Microscopy

Self Cite

This paper reviews the basics of electron holography as an introduction of the holography part of this special issue in Microscopy. We discuss the general principle of holography and interferometry regarding measurements and analyses of phase distributions, first using the optical holography. Next, we discuss physical phenomena peculiar to electron waves that cannot be realized by light waves and principles of electromagnetic field detection and observation methods. Furthermore, we discuss the interference optical systems of the electron waves and their features, and methods of reconstruction of the phase information from electron holograms, which are essential for realization of practical electron holography. We note that following this review application of electron holography will be discussed in detail in the papers of this special issue.

“…However, it was not possible to distinguish which slit electrons passed through when interference fringes were formed. This is because if an electron behaves as a wave, the electron wave is diffracted out after passing through the slit and interference of two electron waves is generated, [29][30][31] even if the propagation distance is short.…”

mentioning

confidence: 99%

Electron interference experiment with optically zero propagation distance for V-shaped double slit

Akashi

Takahashi

et al. 2021

Appl. Phys. Express

Self Cite

In an electron double-slit experiment, an optically zero propagation distance condition (infocus imaging condition), in which the double-slit position was imaged just on the detector plane (image plane), was realized in a 1.2 MV field-emission transmission electron microscope. Interference fringes composed of dot images were controlled by using two electron biprisms. Using a V-shaped double slit, we observed the interference features under the pre-interference condition, interference condition and post-interference condition of electron waves. We conclude that it is possible to observe the interference fringes only when the path information of the individual electrons is not available.