Small-angle scattering interferometry with neutron orbital angular momentum states

TL;DR

This paper introduces a neutron interferometry method to recover phase information in small-angle neutron scattering, enabling detailed analysis of neutron orbital angular momentum states and their interference patterns.

Contribution

It presents a novel interferometry technique that extracts phase profiles from SANS measurements, a significant advancement in neutron orbital angular momentum research.

Findings

First demonstration of petal-structure signatures of helical wave interference

Successful recovery of phase information from SANS measurements

Enhanced capability for material characterization using neutron OAM states

Abstract

Access to the neutron orbital degree of freedom has been enabled by the recent actualization of methods to prepare and characterize neutron helical waves carrying orbital angular momentum (OAM) at small-angle neutron scattering (SANS) facilities. This provides new avenues of exploration in fundamental science experiments as well as in material characterization applications. However, it remains a challenge to recover phase profiles from SANS measurements. We introduce and demonstrate a novel neutron interferometry technique for extracting phase information that is typically lost in SANS measurements. An array of reference beams, with complementary structured phase profiles, are put into a coherent superposition with the array of object beams, thereby manifesting the phase information in the far-field intensity profile. We demonstrate this by resolving petal-structure signatures of helical wave interference for the first time: an implementation of the long-sought recovery of phase information from small-angle scattering measurements.