Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Applied Optics and Photonics China (AOPC)

Design and optimization of grating chip for compact magneto-optical trap

Jing Dong, Xiao‐Kuan Li, Wei Li

Published Oct 28, 2025• 0 citations
Publisher

Abstract

Compared with the conventional three-dimensional magneto-optical trap (3D MOT), the grating magneto-optical trap (GMOT) enables the cooling and trapping of atoms with only a single beam of light, thereby significantly reducing the overall volume of the device. Here, a grating chip with high diffraction efficiency is designed, and its parameters are optimized through simulations, which effectively suppresses the power of the zero-order diffracted light. Subsequently, the grating chip is fabricated and characterized, and using this chip, we successfully trap 1.7×106 atoms. The temperatures of the atomic cloud in the axial and radial directions are 5.6 mK and 17.0 mK, respectively. The successful implementation of the atom cooling and trapping experiment based on the diffraction grating provides important reference for the miniaturization of cold atom-based quantum sensors.

DOI
10.1117/12.3083791

Related papers

Low power consumption grating magneto-optical trap based on planar elements

Zhilong Yu, Yumeng Zhu, Minghao Yao +5 more

The grating-based magneto-optical trap (GMOT) is a promising approach for miniaturizing cold-atom systems. However, the power consumption of a GMOT system dominates its feasibility in practical applications. In this study, we demonstrated a GMOT system based on planar elements that can operate with low power consumption. A high-diffraction-efficiency grating chip was used to cool atoms with a single incident beam. A planar coil chip was designed and fabricated with a low power consumption nested architecture. The grating and coil chips were adapted to a passive pump vacuum chamber, and up to 10 6 87 Rb atoms were trapped. These elements effectively reduce the power consumption of the GMOT and have great potential for applications in practical cold-atom-based devices.

arXiv:2401.08145•Optics Express•Feb 16, 2024•10 citations

A compact high-flux grating chip cold atom source

Hendrik Heine, Aidan S. Arnold, Melanie S Le Gonidec +4 more

Abstract Diffraction gratings have simplified the optical implementation of magneto-optical traps (MOTs) to require only a single input beam, however reaching high atom number and fast loading has proven to be a challenge. We equipped an atom chip with a grating surface and paired it with a velocity-tunable 2D+-MOT as an atomic source to facilitate efficient loading together with magnetic trapping. Using uniform grating illumination, we magneto-optically trap 1.0 ( 1 ) × 10 9 atoms within one second, cool them to 14.1 ( 3 ) μ K , and transfer a quarter of them into the magnetic chip trap. This is a key step towards simple portable quantum sensors employing (ultra-)cold atoms.

New Journal of Physics•Mar 1, 2025•5 citations

High-efficiency 2D grating design for the magneto-optical trap: enhancing intensity balance and reducing optical complexity

Elaheh Karooby, Jiazhen Li, Amit Kumar Agrawal +1 more

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.

Optical Engineering•Aug 21, 2025•4 citations

Diffraction-Engineered Metasurfaces in Magneto-Optical Trapping toward Compact Cold Atom Systems

Thu Hac Huong Le, Sota Kagami, Ryohei Takei +4 more

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.

ACS Photonics•Jun 9, 2026•0 citations

Magneto-optical traps on a chip using micro-fabricated gratings

C. C. Nshii, Matthieu Vangeleyn, Joseph P. Cotter +7 more

We have made magneto-optical traps (MOTs) on a chip which is able to cool and trap ~108atoms directly from a ~1cm3thermal background of87Rb. Diffraction gratings are used to manipulate the light from a single input beam to create the beams required for a MOT [1,2]. The gratings are etched into the surface of a silicon or GaAs wafer by either electron beam, or photo-lithography making them simple to fabricate and integrate into other atom chip architectures. We have developed a variety of gratings for utilisation both inside and outside a vacuum chamber - facilitating their incorporation into both new and existing devices. Unlike previously integrated cold atom sources on a chip [3,4] the atoms now sit above the surface where they can be easily imaged, manipulated and transferred into other on-chip potentials.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•May 1, 2013•0 citations

Two-dimensional grating magneto-optical trap

Eric Imhof, Benjamin Stuhl, Brian L. Kasch +3 more

We demonstrate a two-dimensional (2D) grating magneto-optical trap (GMOT) with a single input cooling laser beam and a planar diffraction grating using $^{87}\mathrm{Rb}$. This configuration increases experimental access when compared with a traditional 2D magneto-optical trap (MOT). As described in the paper, the output flux is several hundred million rubidium atoms/s at a mean velocity of 16.5(9) m/s and a velocity distribution of 4(3) m/s standard deviation. We use the atomic beam from the 2D GMOT to demonstrate loading of a three-dimensional (3D) GMOT with $2.46(7)\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms. Methods to improve output flux are discussed.

arXiv:1703.07926•Physical Review A•Sep 29, 2017•49 citations
Compared with the conventional three-dimensional magneto-optical trap (3D MOT), the grating magneto-optical trap (GMOT) enables the cooling and trapping of atoms with only a single beam of light, thereby significantly reducing the overall volume of the device. Here, a grating chip with high diffraction efficiency is designed, and its parameters are optimized through simulations, which effectively suppresses the power of the zero-order diffracted light. Subsequently, the grating chip is fabricated and characterized, and using this chip, we successfully trap 1.7×106 atoms. The temperatures of the atomic cloud in the axial and radial directions are 5.6 mK and 17.0 mK, respectively. The successful implementation of the atom cooling and trapping experiment based on the diffraction grating provides important reference for the miniaturization of cold atom-based quantum sensors.
The grating-based magneto-optical trap (GMOT) is a promising approach for miniaturizing cold-atom systems. However, the power consumption of a GMOT system dominates its feasibility in practical applications. In this study, we demonstrated a GMOT system based on planar elements that can operate with low power consumption. A high-diffraction-efficiency grating chip was used to cool atoms with a single incident beam. A planar coil chip was designed and fabricated with a low power consumption nested architecture. The grating and coil chips were adapted to a passive pump vacuum chamber, and up to 10 6 87 Rb atoms were trapped. These elements effectively reduce the power consumption of the GMOT and have great potential for applications in practical cold-atom-based devices.
Abstract Diffraction gratings have simplified the optical implementation of magneto-optical traps (MOTs) to require only a single input beam, however reaching high atom number and fast loading has proven to be a challenge. We equipped an atom chip with a grating surface and paired it with a velocity-tunable 2D+-MOT as an atomic source to facilitate efficient loading together with magnetic trapping. Using uniform grating illumination, we magneto-optically trap 1.0 ( 1 ) × 10 9 atoms within one second, cool them to 14.1 ( 3 ) μ K , and transfer a quarter of them into the magnetic chip trap. This is a key step towards simple portable quantum sensors employing (ultra-)cold atoms.
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.
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.
We have made magneto-optical traps (MOTs) on a chip which is able to cool and trap ~108atoms directly from a ~1cm3thermal background of87Rb. Diffraction gratings are used to manipulate the light from a single input beam to create the beams required for a MOT [1,2]. The gratings are etched into the surface of a silicon or GaAs wafer by either electron beam, or photo-lithography making them simple to fabricate and integrate into other atom chip architectures. We have developed a variety of gratings for utilisation both inside and outside a vacuum chamber - facilitating their incorporation into both new and existing devices. Unlike previously integrated cold atom sources on a chip [3,4] the atoms now sit above the surface where they can be easily imaged, manipulated and transferred into other on-chip potentials.
We demonstrate a two-dimensional (2D) grating magneto-optical trap (GMOT) with a single input cooling laser beam and a planar diffraction grating using 87Rb^{87}\mathrm{Rb}87Rb. This configuration increases experimental access when compared with a traditional 2D magneto-optical trap (MOT). As described in the paper, the output flux is several hundred million rubidium atoms/s at a mean velocity of 16.5(9) m/s and a velocity distribution of 4(3) m/s standard deviation. We use the atomic beam from the 2D GMOT to demonstrate loading of a three-dimensional (3D) GMOT with $2.46(7)\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms. Methods to improve output flux are discussed.