NIST's Curved Neutron Beams May Offer Direct Advantages for Industrial Applications

For the first time in physics, researchers—including scientists from the National Institute of Standards and Technology (NIST)—have developed a method to make neutron beams follow curved paths. Known as Airy beams (named after English scientist George Airy), these curved beams were produced using a specially designed device. This breakthrough could improve the way neutrons are used to analyze materials such as pharmaceuticals, perfumes, and pesticides, especially because the beams can bend around obstacles, offering new ways to access hard-to-reach information.

The team's findings were published today in Physical Review Letters. Led by Dusan Sarenac from the University at Buffalo, the research involved collaborators from several institutions, including the Institute for Quantum Computing (IQC) at the University of Waterloo in Canada, which developed the specialized device used to generate the Airy beam. Additional contributors came from the University of Maryland, Oak Ridge National Laboratory, Switzerland’s Paul Scherrer Institute, and Germany’s Jülich Center for Neutron Science at Heinz Maier-Leibnitz Zentrum.

Airy beams don’t just follow curved, parabolic paths — they also exhibit surprising behaviors. Unlike standard beams, such as those from a flashlight, Airy beams do not spread out as they travel. Remarkably, they can also “self-heal”: if part of the beam is obstructed, the remaining portion reconstructs its original shape once past the obstacle.

Although researchers have previously produced Airy beams using particles like photons and electrons, generating them from neutrons posed a unique challenge.

Neutrons lack an electric charge, so they aren’t influenced by electric fields, and they can't be steered using conventional lenses.

To overcome this, the team designed a custom diffraction grating array—a silicon square about the size of a pencil eraser, etched with over six million micro-scale lines. Arranged in precise patterns, these tiny structures manipulate a regular neutron beam, transforming it into an Airy beam.

Although the concept of etching a silicon chip may sound straightforward, determining the precise pattern needed to generate an Airy beam was far from simple.

“It took us years to figure out the correct dimensions for the grating,” said co-author Dmitry Pushin, a faculty member at the Institute for Quantum Computing and professor at the University of Waterloo. “Actually carving the grating at the university’s nanofabrication facility took only about 48 hours, but it required years of preparation and work by a postdoctoral fellow beforehand.”

According to researcher Huber, neutron Airy beams could significantly enhance neutron imaging capabilities. These beams may improve scan resolution and enable scientists to focus on specific regions within an object, benefiting imaging techniques such as neutron scattering and neutron diffraction.

One of the most exciting prospects, Huber added, is the potential to combine neutron Airy beams with other types of neutron beams.

“We believe combining different neutron beams could broaden the Airy beam’s applications,” said Dusan Sarenac. “Researchers could adapt our method to create tailored Airy beams for specific physical or material studies.”

For instance, scientists could merge a neutron Airy beam with a helical neutron wave—a beam structure the team previously developed over a decade ago. This combination could enable deeper exploration of chirality—a property where molecules exist in two mirror-image forms, each with distinct behaviors and effects.

A more advanced method for analyzing chirality could transform the design of chiral molecules, which are essential in pharmaceuticals, materials science, and chemical production. The global market for chiral drugs alone is valued at over $200 billion, and chiral catalysis plays a key role in manufacturing a wide range of chemical products.

Chirality is becoming increasingly significant in quantum computing and advanced electronic technologies like spintronics.

“A material’s chirality can affect electron spin, which is crucial for using spin-polarized electrons in data storage and processing,” explained Huber. “Being able to control chirality could also enhance our ability to manipulate qubits, the fundamental units of quantum computing. Neutron Airy beams may offer a much more effective way to investigate materials with these advanced properties.”