Metasurface holograms unlock ultra-dense single-atom tweezer arrays

Researchers demonstrate trapping of single strontium atoms in two‑dimensional metasurface‑generated optical tweezer arrays, achieving arbitrary geometries with trap spacings as small as 1.5 μm and over 100 traps, with high uniformity in depth and frequency. The metasurfaces (silicon-rich silicon nitride and TiO2) use subwavelength pixels to scale far beyond current limits, enabling a 360,000‑trap array and a path toward scalable neutral-atom quantum technologies.