Abstract The planar-integrated magneto-optical trap (PIMOT) offers a promising platform for miniaturizing cold atom systems, but its performance and laser-power efficiency are limited by the typically Gaussian profile of the input laser beam. In this work, we present a simplified and cost-effective beam shaping solution to transform the Gaussian input into a flat-top intensity distribution using a compact system of four spherical lenses. The reshaped light field could potentially enhances PIMOT performance by improving the uniformity of the optical radiation pressure and increasing the trap distance from the chip surface. With this approach, we demonstrate a substantial reduction in the optical power required to trap 2.5 × 10 5 87 Rb atoms, down to 30% compared to a standard Gaussian beam input. Our results open the door to more efficient and flexible PIMOT systems for quantum sensing, metrology, and atom-based quantum technology.
Abstract The planar-integrated magneto-optical trap (PIMOT) offers a promising platform for miniaturizing cold atom systems, but its performance and laser-power efficiency are limited by the typically Gaussian profile of the input laser beam. In this work, we present a simplified and cost-effective beam shaping solution to transform the Gaussian input into a flat-top intensity distribution using a compact system of four spherical lenses. The reshaped light field could potentially enhances PIMOT performance by improving the uniformity of the optical radiation pressure and increasing the trap distance from the chip surface. With this approach, we demonstrate a substantial reduction in the optical power required to trap 2.5 × 10 5 87 Rb atoms, down to 30% compared to a standard Gaussian beam input. Our results open the door to more efficient and flexible PIMOT systems for quantum sensing, metrology, and atom-based quantum technology.
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.
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.
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.
Integrated diffraction gratings offer a compact route to magneto-optical traps (MOTs) for atom cooling and trapping, thus preparing MOTs for future scalable quantum systems. Although segmented tri-gratings ensure axial radiation pressure balance, they are limited in optical trapping volume. Planar 2D gratings, though offer larger trapping regions, suffer from low diffraction efficiency and the resulting axial pressure imbalance, necessitating the use of a neutral density (ND) filter to achieve this balance. We present a numerically optimized 2D diffraction grating design that overcomes these limitations and satisfies the required optical conditions for laser cooling, namely, radiation pressure balance, specular reflection cancellation, and circular polarization handedness reversal upon diffraction, thus achieving an optical molasses—a necessary condition in MOT. Using rigorous coupled-wave analysis and a genetic algorithm, we design a grating for Rb87 grating MOT (GMOT) that achieves a 24% first-order diffraction efficiency, of which 99.7% have the correct circular handedness. These properties enable efficient atom cooling without an ND filter when used with a flat-top beam inside the vacuum chamber. Our design simplifies optical alignment, reduces system footprint, and advances the integration of GMOTs into compact quantum devices.
The magneto-optical trap (MOT) is an essential tool for collecting and preparing cold atoms with a wide range of applications. We demonstrate a planar-integrated MOT by combining an optical grating chip with a magnetic coil chip. The flat grating chip simplifies the conventional six-beam configuration down to a single laser beam, and the flat coil chip replaces the conventional anti-Helmholtz coils of cylindrical geometry. Up to 106 cold 87Rb atoms are trapped by the planar-integrated MOT, with the atom cloud being approximately 6mm above the chip surface. This configuration effectively reduces the volume, weight, and complexity of the MOT, bringing benefits to applications including gravimeter, clock, and quantum memory devices.
Abstract We present a compact cold atom platform where an optical grating chip and planar coil chip are placed inside a compact vacuum chamber to create a magneto-optical trap. This approach significantly reduces the system volume to about 20 × 20 × 20 cm3 compared to conventional vacuum systems and offers greater flexibility in accessing the trapped atoms. We demonstrate the trapping of 3 × 105 cold rubidium atoms at a temperature of 100 μK in a vacuum pressure below 10−7 mbar. The simplified optical geometry, low power consumption, and high degree of integration make this a promising platform for portable and versatile cold-atom devices in quantum sensing, timing, and information processing.