Magneto-optical traps (MOTs), indispensable to cold-atom-based quantum computing and quantum precision measurement, are increasingly desired in compact and stable form. Particularly, the six-beam 3D-MOT, distinguished by symmetric geometry and superior trapping performance, finds particularly broad applications. Conventional implementations, however, rely on complex and bulky free-space optics, hindering miniaturization, practical assembly, and long-term stability. Here, we demonstrate a compact six-beam 3D-MOT system that employs two multifunctional optical metasurface chips to implement the optical-field functionalities required for cooling and trapping atoms. By combining two metasurface chips and a vacuum cell, a photonic-integrated cell module (PICM) is implemented as the core assembly and the volume is only" 73*73*107 mm^3" . In success, 1.3 * 10^3 Rb atoms are trapped and cooled to the temperature of ~183 μK. It should be noticed that the laser beam is guided to the metasurface through optical fiber, thus such fully fiber-coupled architecture enables straightforward and stable operations. We believe that this work would pave a practical route toward compact and portable 3D-MOT.
Magneto-optical traps (MOTs), indispensable to cold-atom-based quantum computing and quantum precision measurement, are increasingly desired in compact and stable form. Particularly, the six-beam 3D-MOT, distinguished by symmetric geometry and superior trapping performance, finds particularly broad applications. Conventional implementations, however, rely on complex and bulky free-space optics, hindering miniaturization, practical assembly, and long-term stability. Here, we demonstrate a compact six-beam 3D-MOT system that employs two multifunctional optical metasurface chips to implement the optical-field functionalities required for cooling and trapping atoms. By combining two metasurface chips and a vacuum cell, a photonic-integrated cell module (PICM) is implemented as the core assembly and the volume is only" 7373107 mm^3" . In success, 1.3 * 10^3 Rb atoms are trapped and cooled to the temperature of ~183 μK. It should be noticed that the laser beam is guided to the metasurface through optical fiber, thus such fully fiber-coupled architecture enables straightforward and stable operations. We believe that this work would pave a practical route toward compact and portable 3D-MOT.
Abstract Cold atoms are important for precision atomic applications including timekeeping and sensing. The 3D magneto-optical trap (3D-MOT), used to produce cold atoms, will benefit from photonic integration to improve reliability and reduce size, weight, and cost. These traps require the delivery of multiple, large area, collimated laser beams to an atomic vacuum cell. Yet, to date, beam delivery using an integrated waveguide approach has remained elusive. Here we report the demonstration of a 87 Rb 3D-MOT using a fiber-coupled photonic integrated circuit to deliver all beams to cool and trap > 1 ×10 6 atoms to near 200 μK. The silicon nitride photonic circuit transforms fiber-coupled 780 nm cooling and repump light via waveguides to three mm-width non-diverging free-space cooling and repump beams directly to the rubidium cell. This planar, CMOS foundry-compatible integrated beam delivery is compatible with other components, such as lasers and modulators, promising system-on-chip solutions for cold atom applications.
Cold atoms produced in magneto-optical traps (MOTs) have underpinned advances in emerging quantum technologies, including quantum computing, precision metrology, and fundamental physics. Grating-based MOT (gMOT), which employs a reflective diffraction grating to enable laser cooling from a single incident beam, offers a compact alternative to conventional six-beam MOTs. However, the inherent asymmetry of gMOT beam geometry can compromise the trapping stability and efficiency, particularly for atomic species with complex internal level structures. Here, we present a geometric-phase dielectric metasurface that simultaneously engineers the transmitted and diffracted wavefronts with desired polarization states, enabling full MOT operation under axial illumination using a single planar optical element. This metasurface-based architecture restores the symmetry in the trapping forces while preserving the compactness and simplicity of gMOTs. Using this approach, we demonstrate the trapping and cooling of cesium─an atomic species widely regarded as challenging for standard gMOT implementations─and analyze the trapping mechanism through numerical calculations. By providing independent control over key trapping parameters within a planar and alignment-simplified platform, this work establishes a route toward compact, robust, and species-flexible cold-atom systems, thereby expanding the applicability of miniaturized MOTs for integrated quantum technologies.
Compact, lightweight, and energy-efficient cold-atom systems are foundational for the development of deployable quantum technologies, yet their realization remains largely constrained due to reliance on bulky optical and magnetic components. Here, we demonstrate a record-low-SWaP (size, weight, and power) magneto-optical trap architecture seamlessly integrating planar photonic and magnetic components into a monolithic, scalable, and manufacturable platform. This is achieved by developing a multifunctional metasurface that converts a linearly-polarized Gaussian beam into a circularly-polarized flat-top beam (FTB), replacing conventional lens-waveplate assemblies. In parallel, a planar magnetic coil chip substitutes bulky anti-Helmholtz coils and generates the required quadrupole magnetic field with substantially reduced power consumption. Using D 2 line cooling of 87 Rb atoms, the fully planar system achieves nearly an order-of-magnitude improvement in trapped-atom number while operating at a fraction of the SWaP of traditional implementations. This planar integration strategy provides an energy-efficient and scalable pathway toward robust, deployable cold-atom platforms.
Abstract Laser-cooled atoms are a key technology for many calibration-free measurement platforms—including clocks, gyroscopes, and gravimeters—and are a promising system for quantum networking and quantum computing. The optics and vacuum hardware required to prepare these gases are often bulky and not amenable to large-volume manufacturing, limiting the practical realization of devices benefiting from the properties of cold atoms. Planar, lithographically produced optics including photonic integrated circuits, optical metasurfaces (MSs), and gratings offer a pathway to develop chip-scale, manufacturable devices utilizing cold atoms. As a demonstration of this technology, we have realized laser cooling of atomic Rb in a grating-type magneto-optical trap (MOT) using planar optics for beam launching, beam shaping, and polarization control. Efficient use of available light is accomplished using MS-enabled beam shaping, and the performance of the planar optics MOT is competitive with Gaussian-beam illuminated grating MOTs.
The creation of cold atoms underpins quantum sensing and precision metrology, computing, timekeeping, and fundamental science experiments. Miniaturizing the lasers and optical infrastructure, which occupy over 80% of the volume of these experiments, through photonic integration could improve robustness, reliability, and manufacturability while reducing cost and enabling portable space-based precision measurements and quantum tools for non-experts. Yet, there has been limited progress towards integration of the laser and optical infrastructure required to generate cold atoms onto a single chip. We demonstrate a photonic engine that generates, controls, and delivers precision light to create cold atoms in a rubidium 3-dimensional magneto-optical trap (3D-MOT). We integrate on a single chip two frequency-agile self-injection-locked lasers, laser frequency and intensity control, passive beam combining and splitting, signal monitoring, and high-efficiency beam delivery to a rubidium vapor cell. The integrated engine is shown to support multiple functions required for generating cold atoms including stable generation of low-noise cooling and repump light, frequency control for atom spectroscopy and stabilization, real-time laser monitoring, routing for laser offset locking, optical power modulation, and large-area three-beam delivery of 3 mW to the physics package. Fully electrically controlled, the engine enables sustained 3D-MOT operation, trapping more than 1 million atoms at an average temperature of 350 uK and supporting atom-number and temperature measurements. These results demonstrate the first single-chip integration of light generation, control, and delivery for cold-atom generation, offering a path toward smaller, more robust, and manufacturable cold-atom systems for applications including cold-atom clocks and sensors.
Compact, lightweight, and energy-efficient cold atom systems are crucial for advancing quantum technologies, yet their realization remains constrained by the bulky optical and magnetic components required in current atom trapping architectures. Here, we demonstrate a low-SWaP magneto-optical trap that seamlessly integrates planar optical and magnetic components into a unified platform. A monolithic dual-functional metasurface simultaneously polarized and shapes the cooling beam, replacing traditional lens-waveplate assemblies and converting a linearly polarized Gaussian beam into a circularly polarized flat-top beam. In parallel, a planar coil chip substitutes bulky anti-Helmholtz cols and generated the required quadrupole magnetic field with drastically reduced power consumption. Under D2 line cooling of 87Rb atoms, the fully planar system delivers nearly an order-of-magnitude improvement in trapping performance while operating at a fraction of the size, weight, and power of traditional systems. This compact, bulky-component-free approach offers a scalable, energy-efficient pathway toward chip-scale cold atom platforms.