Vortex beams of atoms and molecules

Vortex beams of nonelementary particles The discovery of photon and electron vortex beams carrying orbital angular momentum (as a result of a twisting wave front) has led to appreciable advances in optical imaging, optical and electron microscopy, communications, quantum optics and micromanipulation, and more advances are expected. In an effort to extend this progress to other types of beams, Luski et al . demonstrate the production of vortex beams of helium atoms and dimers formed from supersonic beams with large coherence lengths diffracted off of specifically nanofabricated gratings with fork dislocations (see the Perspective by Kornilov). Vortex beams made of nonelementary particles with internal degrees of freedom represent a direct manifestation of quantum mechanics on macroscopic scale, and their production paves the way for many long-awaited applications. —YS