Figure 1

Generation of electron vortex beams with user-selected OAM using a fork-type aperture. (a) Scanning electron microscope image of a 50 µm dislocation aperture (places at the C2 aperture level). The horizontal ligaments are used as reinforcement of the 200 nm thick Pt foil. (b) Image of the electron probe at the sample. The position of the selected probe (L = +1) with respect to the discriminator aperture at the C3 aperture level is illustrated by the overlaid yellow structure. (c) Intensity profile across the probe (in arbitrary units). The signature donut shape of the outer vortices with |L| = 1 is reflected by a dip in the intensity distribution of these (partial) probes.