Silicon-on-sapphire metasurfaces generate arrays of dark and bright traps for neutral atoms

ACS Photonics (2026)

 
Scientists developed tiny, specially patterned optical devices called metasurfaces that can shape a laser beam into large arrays of optical traps for holding individual atoms. Some of the traps are bright optical tweezers, where atoms are held in regions of intense light, while others are dark “bottle” traps, where atoms are confined in regions surrounded by light but sit in the dark. Dark traps are useful because they reduce unwanted interactions between the light and the atoms.

The metasurfaces are made from crystalline silicon on sapphire, a material that is compatible with the same manufacturing techniques used to make computer chips. Compared with the programmable optical devices commonly used today, these metasurfaces are much smaller, produce less noise, and can create far larger arrays of atom traps.

To make the complex trapping patterns, the researchers developed a new design algorithm that precisely controls the shape of the laser beam. They then fabricated the devices and demonstrated that they can generate arrays of bright traps, dark traps or combinations of both, a useful development for quantum computing and sensing.

The paper’s authors are Chengyu Fang, Minjeong Kim, Hongyan Mei, Xuting Yang, Zhaoning Yu, Yuzhe Xiao, Sanket Deshpande, Preston Huft, Alan Dibos, David A. Czaplewski, Mark Saffman, Jennifer Choy and Mikhail Kats, who conducted their research at the University of Wisconsin–Madison and Argonne National Laboratory.