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

Design and Performance Analysis of Diffractive Chips for Compact magneto-optical traps

Elaheh Karooby, Jiazhen Li, Amit Kumar Agrawal, Qing Gu

Published Jan 1, 2026• 0 citations
Publisher

Abstract

We design a high-efficiency diffractive grating chip and theoretically evaluate its performance using radiation-force modeling for compact magneto-optical traps (MOTs). The design achieves over 96% axial radiation-pressure balance without a neutral-density filter, enabling simplified and compact cold-atom systems.
DOI
10.1364/cleo_at.2026.jw1.107

Related papers

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

Jing Dong, Xiao‐Kuan Li, Wei Li

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.

Applied Optics and Photonics China (AOPC)•Oct 28, 2025•0 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

Diffractive chips for magneto-optical trapping of two atomic species

Zhaoning Yu, Garrett Hickman, Mark E. Saffman +1 more

Grating-based structures have recently been used as components of magneto-optical traps (MOT) to simplify the setup for trapping Rb atoms. Here, we design diffractive chips to trap more than one atom species. Our full-wave simulations show that a two-dimensional (2D) grating chip can simultaneously have high force-balancing efficiency for a wavelength of 780 nm for trapping Rb atoms and a wavelength of 852 nm for Cs atoms. We fabricated and characterized a mm-scale grating chip using electron-beam lithography, and are in the process of trapping experiments. Our work opens the door to compact multi-species MOTs.

Quantum Nanophotonic Materials, Devices, and Systems•Aug 20, 2020•0 citations

Multiphysics Modeling of Grating Chips for Magneto-Optical Trapping of Atoms

Sanket Deshpande, Zhaoning Yu, Jin Zhang +6 more

We present a modeling method that incorporates full-wave electromagnetic simulations and radiation force calculations to evaluate the performance of grating chips for compact megneto-optical traps (MOTs).

Conference on Lasers and Electro-Optics•Jan 1, 2022•0 citations

Phase-space properties of magneto-optical traps utilising micro-fabricated gratings

J. P. McGilligan, P. F. Griffin, Erling Riis +1 more

We have used diffraction gratings to simplify the fabrication, and dramatically increase the atomic collection efficiency, of magneto-optical traps using micro-fabricated optics. The atom number enhancement was mainly due to the increased beam capture volume, afforded by the large area (4cm(2)) shallow etch (~ 200nm) binary grating chips. Here we provide a detailed theoretical and experimental investigation of the on-chip magneto-optical trap temperature and density in four different chip geometries using (87)Rb, whilst studying effects due to MOT radiation pressure imbalance. With optimal initial MOTs on two of the chips we obtain both large atom number (2×10(7)) and sub-Doppler temperatures (50 μK) after optical molasses.

arXiv:1503.01702•Optics Express•Mar 31, 2015•55 citations

Design and optimization of a high-efficiency and robust 2D grating for the magneto-optical trap

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

Diffraction gratings integrated into an atomic, molecular, and optical (AMO) setup offer a compact and efficient route toward atom cooling and trapping, thus preparing magneto-optical traps (MOT) for insertion into future scalable quantum systems. Here, we propose and numerically validate a two-dimensional (2D) grating that satisfies the required optical conditions for laser cooling: radiation pressure balance, specular reflection cancellation, and circular polarization handedness reversal upon diffraction. The grating, composed of a 2D array of cylindrical nanoholes, is optimized using RCWA in combination with a Genetic Algorithm (GA). It efficiently diffracts normally incident 780 nm circularly polarized light into the four first orders, each achieving a diffraction efficiency of 0.24, of which 99.7% has the correct circular handedness. This design significantly improves axial radiation pressure balance, potentially eliminating the need for the neutral density (ND) filters that were previously required in grating-MOTs (GMOTs) employing 2D gratings to compensate for the radiation pressure imbalance. The grating's robustness ensures manufacturing resilience.

Low-Dimensional Materials and Devices•Sep 17, 2025•0 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.
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.
Grating-based structures have recently been used as components of magneto-optical traps (MOT) to simplify the setup for trapping Rb atoms. Here, we design diffractive chips to trap more than one atom species. Our full-wave simulations show that a two-dimensional (2D) grating chip can simultaneously have high force-balancing efficiency for a wavelength of 780 nm for trapping Rb atoms and a wavelength of 852 nm for Cs atoms. We fabricated and characterized a mm-scale grating chip using electron-beam lithography, and are in the process of trapping experiments. Our work opens the door to compact multi-species MOTs.
We have used diffraction gratings to simplify the fabrication, and dramatically increase the atomic collection efficiency, of magneto-optical traps using micro-fabricated optics. The atom number enhancement was mainly due to the increased beam capture volume, afforded by the large area (4cm(2)) shallow etch (~ 200nm) binary grating chips. Here we provide a detailed theoretical and experimental investigation of the on-chip magneto-optical trap temperature and density in four different chip geometries using (87)Rb, whilst studying effects due to MOT radiation pressure imbalance. With optimal initial MOTs on two of the chips we obtain both large atom number (2×10(7)) and sub-Doppler temperatures (50 μK) after optical molasses.
Diffraction gratings integrated into an atomic, molecular, and optical (AMO) setup offer a compact and efficient route toward atom cooling and trapping, thus preparing magneto-optical traps (MOT) for insertion into future scalable quantum systems. Here, we propose and numerically validate a two-dimensional (2D) grating that satisfies the required optical conditions for laser cooling: radiation pressure balance, specular reflection cancellation, and circular polarization handedness reversal upon diffraction. The grating, composed of a 2D array of cylindrical nanoholes, is optimized using RCWA in combination with a Genetic Algorithm (GA). It efficiently diffracts normally incident 780 nm circularly polarized light into the four first orders, each achieving a diffraction efficiency of 0.24, of which 99.7% has the correct circular handedness. This design significantly improves axial radiation pressure balance, potentially eliminating the need for the neutral density (ND) filters that were previously required in grating-MOTs (GMOTs) employing 2D gratings to compensate for the radiation pressure imbalance. The grating's robustness ensures manufacturing resilience.