The magneto-optical trap (MOT) is a key technology for cooling and trapping neutral atoms, widely used in quantum precision measurement, atomic clocks, quantum simulation, and computing. However, traditional MOT systems rely on complex bulk optical components (such as waveplates, mirrors, prisms, etc.) to generate and control six mutually orthogonal circularly polarized cooling laser beams, which limits their portability and integration potential. In recent years, although miniaturization schemes based on gratings or planar integrated photonics (PIC) have reduced the system size, they still face challenges such as requiring additional bulky optical devices and limited atom trapping capability. To address these challenges, our laboratory has proposed a novel miniaturized MOT beam delivery system based on meta-devices. The core of this system is a new type of polarization-decoupling multi-port beam-splitting (PD-MPBS) metasurface, which integrates multiple beam splitting and independent polarization control by combining propagation phase and geometric phase. The fabricated PD-MPBS samples exhibit high beam-splitting power uniformity (power variation <4.4%) and high polarization purity (91.3%~93.2%). By integrating reflective beam-expanding metasurfaces, the authors successfully implemented a fully metasurface-based miniaturized six-beam delivery system. Experimental results demonstrate uniform power distribution (power variation <9.5%), desired circular polarization configuration (purity 88.5%~90.6%), and a large overlapping volume (76.2 mm³). This achievement provides important technical support for portable cold-atom technology applications in precision measurement, quantum computing, and other fields. This work was published on 13^th July, 2025 in the journal of Advanced Science (Impact Factor: 14.1). Ph.D. student Tian Tian is the first author of this paper, and Professor Xue Feng, Professor Dengke Zhang (Beihang University) and Professor Yidong Huang are the corresponding authors of the paper.

The link of article: https://doi.org/10.1002/advs.202506289