Orbital angular momentum-resolved convergent-beam electron diffraction by the post-selected injection of electron beam.

Recent advances in the production of electron vortex beams carrying orbital angular momentum (OAM) offer unique opportunities to explore materials at the nanoscale level. We present a novel method for observing convergent-beam electron diffraction (CBED) patterns by using an electron vortex beam. In a transmission electron microscope, a series of electron vortex beams generated by a forked grating mask located above the specimen illuminate the specimen, and CBED patterns are imaged onto the observation plane of the microscope, selecting one of the electron vortex beams using an aperture located beneath the specimen.

Nearly nondiffracting electron lattice beams generated by polygonal slits.

A method for generating electron lattice beams carrying vortices using nanofabricated polygonal slits in a transmission electron microscope is proposed. Experimental and simulation study of the intensity of the beams verified their Bessel beam-like nearly nondiffracting behavior. Phase analysis using a diffractive imaging method found arrays of quantized vortices, forming an electron beam lattice with cylindrical intensity distribution in the propagation direction.