Electron holography for vortex beams

Abstract

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.

Soft X-ray Vortex Beam detected by In-line Holography

“…As similar intensity patterns have been observed in visible light and electron vortex beams [16,19], it is known that such interference patterns require a reference beam from an incline direction. To gain a further understanding of the intensity distribution shown in Figs.…”

“…Another interference method is inline (Gabor's) holography, in which a reference wave and a diffracted wave scattered by an object share the same optical axis. The usefulness of this technique has been demonstrated in electron vortex beams for obtaining spiral phase distributions [18,19]. Hence, in the present study, we focus on observing of the phase information of soft x-ray vortices generated by a diffractive optical element via coherent soft x-ray in-line holography.…”