Nanowerk April 23, 2024
Almost all the experimentally created electron vortex beam (EVBs) manifest isotropic doughnut intensity patterns. Based on the correlation between local divergence angle of electron beam and phase gradient along azimuthal direction, researchers in China showed that free electrons could be tailored to EVBs with customizable intensity patterns independent of the carried OAM. As proof-of-concept, by using computer generated hologram and designing phase masks to shape the incident free electrons they tailored three structured EVBs carrying identical OAM to exhibit completely different intensity patterns. Through the modal decomposition, they quantitatively investigated their OAM spectral distributions and revealed that structured EVBs present a superposition of a series of different eigenstates induced by the locally varied geometries. According to the researchers their results generalized the concept of EVB, and demonstrated a highly controllable degree of freedom for electron beam manipulation in addition to OAM… read more. Open Access TECHNICAL ARTICLEÂ
Schematic of the generation of structured EVBs. Credit: Opto-Electronic Advances, Vol. 7, No. 2, 230184, 26 February 2024