A Centimeter-Scale Dielectric Metasurface for the Generation of Cold Atoms

The single-beam magneto-optical trap (MOT) based on the diffractive optical element offers a new route to develop compact cold atom sources. However, the optical efficiency in the previous single-beam MOT systems is usually low and unbalanced, which will affect the quality of the trapped atoms. To solve this issue, we developed a centimeter-scale dielectric metasurface optical chip with dynamic phase distributions, which was used to split a single incident laser beam into five separate ones with well-defined polarization states and uniform energy distributions. The measured diffraction efficiency of the metasurface is up to 47%. A single-beam MOT integrated with the metasurface optical chip was then used to trap the ⁸⁷Rb atoms with numbers ∼1.4 × 10⁸ and temperatures ∼7.0 μK. The proposed concept in this work may provide a promising solution for developing ultracompact cold atom sources.