Topological shaping of vortex neutron beams using forked phase gratings

Abstract

Beams of light or matter that carry well-defined states of orbital angular momentum (OAM) are promising probes of topological and textured condensed matter systems such as magnetic skyrmions. Using spin-echo small-angle neutron scattering (SESANS), we demonstrate the production of vortex neutron beams from forked phase gratings of various topological charges. In contrast to some previous techniques used to verify OAM production, SESANS is a more precise measurement of the neutron's OAM as it is a phase-sensitive, interferometric technique that directly measures the phase between the scattered neutron spin states.