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

Journal of the Optical Society of America B

Influence of cooling lights’ low-frequency pointing instability on the quality of magneto-optical trapping

Xu Zhang, Yaning Wang, Qixue Li, Lingxiao Zhu, Yuan Sun, Aiai Jia, Huankai Zhang, Mengjie Lv, Shuhua Yan, Jun Jie Yang

Published Nov 22, 2019• 2 citations
Publisher

Abstract

In recent years, rapid progress has been made in the research areas of quantum sensing, which leads to more and more interest in field applications of high-precision sensors based upon cold atoms. Since magneto-optical trapping (MOT) serves as the mainstream technological platform to generate cold atoms, it is then natural to question its stability under harsh conditions of field operations, such as mechanical vibrations and acoustic noises, and this motivates our research work. In this article, we report our recent study of MOT quality when the cooling lasers are suffering instabilities from low-frequency acoustic vibrations, both theoretically and experimentally. We have implemented numerical simulations for a MOT capturing process under the presence of such instabilities, which reveals the kinematics of atoms for this scenario. Meanwhile, we have carried out experiments to test the outcome, especially by resorting to the time-of-light measurements, where acoustic vibrations are introduced to the cooling lights of MOT in a controlled manner. We demonstrate that a properly constructed MOT is robust against the low-frequency vibrations of cooling lights. Moreover, we also discuss potential applications of assessing MOT properties by the method of applying prescribed vibrations to cooling lights.

DOI
10.1364/josab.36.003531

Related papers

Conveyor-belt magneto-optical trapping of molecules

Kehui Li, Christian Hallas, John M. Doyle

Abstract Laser cooling is used to produce ultracold atoms and molecules for quantum science and precision measurement applications. Molecules are more challenging to cool than atoms due to their vibrational and rotational internal degrees of freedom. Molecular rotations lead to the use of type-II transitions ( F ⩾ F ′ ) for magneto-optical trapping (MOT). When typical red detuned light frequencies are applied to these transitions, sub-Doppler heating is induced, resulting in higher temperatures and larger molecular cloud sizes than realized with the type-I MOTs most often used with atoms. To improve type-II MOTs, Jarvis et al (2018 Phys. Rev. Lett. 120 083201) proposed a blue-detuned MOT to be applied after initial cooling and capture with a red-detuned MOT. This was successfully implemented (Burau et al 2023 Phys. Rev. Lett. 130 193401; Jorapur et al 2024 Phys. Rev. Lett. 132 163403; Li et al 2024 Phys. Rev. Lett. 132 233402), realizing colder and denser molecular samples. Very recently, Hallas et al (2024 arXiv:2404.03636) demonstrated a blue-detuned MOT with a ‘1+2’ configuration that resulted in even stronger compression of the molecular cloud. Here, we describe and characterize theoretically the conveyor-belt mechanism that underlies this observed enhanced compression. We perform numerical simulations of the conveyor-belt mechanism using both stochastic Schrödinger equation and optical Bloch equation approaches. We investigate the conveyor-belt MOT characteristics in relation to laser parameters, g-factors and the structure of the molecule, and find that conveyor-belt trapping should be applicable to a wide range of laser-coolable molecules.

arXiv:2409.18090•New Journal of Physics•Mar 13, 2025•9 citations

Enhanced Atom Capture via Multi-Frequency Magneto-Optical Trapping

Benjamin Hopton, Alexander Abbey, David Johnson +6 more

Magneto-optical traps are central to atomic and molecular quantum technologies and precision tests of fundamental physics, where both sensitivity and bandwidth scale strongly with atom number and loading rate. We demonstrate that employing multiple, closely spaced optical frequency components in the cooling light of a $^{87}$Rb magneto-optical trap -- without utilizing any additional slowing techniques -- can double the steady state atom number and increase the loading rate by up to a factor of 4, compared to a conventional single-frequency implementation. Subsequently, we capture up to $1.0(1)\times10^{10}$ atoms with a loading rate of up to $1.3(2)\times 10^{11}\,\mathrm{atoms\,s^{-1}}$ from a thermal background. Numerical simulations reproduce the observed trends and predict substantially larger gains for increased trap sizes beyond our experimental bounds. By re-examining earlier studies of multi-frequency atom capture in the context of modern experimental hardware and emerging applications, we show that previously identified limitations can be avoided and establish multi-frequency cooling as a practical and scalable route to high-flux cold-atom sources. These results have immediate applications in portable atom-based quantum sensing, where higher bandwidth and precision can be achieved without forgoing compactness, and in atom-interferometric tests of fundamental physics, which benefit from access to larger-mass quantum systems.

physics.atom-phCross-listedarXiv:2604.23221•Apr 28, 2026•0 citations

Accurate absolute measurement of trapped Cs atoms in a MOT

M.A. Talavera

A Cs-133 Magneto-Optical Trap (MOT) has been developed at the Time and Frequency Division of the Centro Nacional de Metrolog´ CENAM, in Mexico. This MOT is part of a primary frequency standard based on ultra-cold Cs atoms, called CsF-1 clock, under development at CENAM. In this Cs MOT, we use the standard configuration (ae + i ae i ) 4-horizontal 2-vertical laser beams 1.9 cm in diameter, with 5 mW each. We use a 852 nm, 5 mW, DBR laser as a master laser which is stabilized by saturation spectroscopy. Emission linewidth of the master laser is 1 MHz. In order to amplify the light of the master laser, a 50 mW, 852 nm AlGaAs laser is used as slave laser. This slave laser is stabilized by light injection technique. A 12 MHz red shift of the light is performed by two double passes through two Acusto-Optic Modulators (AOMs). The optical part of the CENAMs MOT is very robust against mechanical vibration, acoustic noise and temperature changes in our laboratory, because none of our diode lasers use an extended cavity to reduce the linewidth. In this paper, we report results of our MOT characterization as a function of several operation parameters such as the intensity of laser beams, the laser beam diameter, the red shift of light, and the gradient of the magnetic field. We also report accurate absolute measurement of the number of Cs atoms trapped in our Cs MOT. We found up to6 £ 10 7 Cs atoms trapped in our MOT measured with an uncertainty no greater than 6.4%.

•Jan 1, 2007•1 citation

The Theory and Operation of Magneto- Optical and Far-Off-Resonance Traps

Mary Lyon

The advent of the magneto-optical trap (MOT) introduced to the field of atomic physics an unprecedented surge in research opportunities and the potential for widespread application in relating fields, such as those of quantum computation, quantum optics, laser physics, and plasma physics. The MOT makes use of a process called laser cooling, whereby atoms can be manipulated through the absorption and emission of photons, in conjunction with inhomogeneous magnetic fields, to cool atoms to kinetic temperatures as low as 200 µK and contain them in a region of space. This process has given researchers a remarkable level of control and has provided the means for extensive

•Jan 1, 2006•0 citations

Realization of the Compact Magneto-Optical Trap Based on Single Laser with Frequency Modulation

Shuning Bao, Bin Wu, Pengfei Cao +9 more

In cold atom physics, the complexity of traditional magneto-optical trap system limits the use of their associated instruments for field applications in atomic physics, such as gravity mapping, space navigation and deep space exploration. This study introduces a novel compact MOT design that addresses these issues by simplifying the structure and reducing the size. The height of the unit is 0.7 m, the volume is 6.3×10−2m3 and the mass is 11.32 kg. The new design utilizes a single laser to generate the two different frequencies needed for laser cooling by internally splitting the beam, shifting the frequency and then combining them, effectively controlling both the cooling and repumping beams. The compact vacuum chamber optical path, in conjunction with the magnetic field, facilitates the capture of 87Rb atoms in an ultra-high vacuum environment. Experimental results demonstrate an atom loading rate of up to 1.79×10787Rb atoms per second, confirming the system’s effectiveness in capturing and cooling 87Rb atoms. This design provides a flexible and portable solution, offering valuable insights for the advancement of compact MOT and its applications in cold atom physics.

Photonics•Jan 23, 2025•0 citations

The blue-detuned magneto-optical trap

K. N. Jarvis

It has been more than 30 years since the first demonstration of a magneto-optical trap (MOT) using sodium atoms. Since then the MOT has revolutionised the field of atomic physics by facilitating the emergence of a broad range of productive avenues of research using atoms prepared at low temperatures and high densities. This thesis describes the development of a novel kind of magneto-optical trap: the blue-detuned MOT. Unlike in all previous MOTs the light is blue detuned from atomic resonances and drives "type-II" transitions that have dark ground-state sub-levels. A discussion of the position-dependent and velocity-dependent forces experienced by an atom or molecule in a MOT is first used to consolidate recent theoretical work and, in particular, to introduce the concept of a blue-detuned MOT. The design and construction of an experiment that has been built to demonstrate a blue-detuned MOT using \Rb{87} is described. A thorough characterisation of this novel MOT has been performed. At high magnetic field gradients, radiation-pressure-limited densities exceeding $10^{11}$~cm$^{-3}$ have been reached whilst temperatures are cooled below 30~\si{\micro K} by the efficient and robust sub-Doppler cooling mechanisms. The maximum phase-space density measured is $6\times10^{-6}$, which is higher than in most normal atomic MOTs, comparable to the best dark SPOTs, and a million times higher than that reported for red-detuned type-II MOTs. This makes the blue-detuned MOT particularly attractive for molecules where laser cooling and trapping always uses type-II transitions. For the first time, a study of trap loss due to ultra-cold collisions between atoms occurring in the presence of near-resonant blue-detuned light is undertaken. Finally, the experiment is used to demonstrate many new and unreported configurations of MOT for \Rb{87}, showing that a comprehensive understanding of complicated MOTs is now possible, and presenting a clear direction for further research.

•May 1, 2018•0 citations
In recent years, rapid progress has been made in the research areas of quantum sensing, which leads to more and more interest in field applications of high-precision sensors based upon cold atoms. Since magneto-optical trapping (MOT) serves as the mainstream technological platform to generate cold atoms, it is then natural to question its stability under harsh conditions of field operations, such as mechanical vibrations and acoustic noises, and this motivates our research work. In this article, we report our recent study of MOT quality when the cooling lasers are suffering instabilities from low-frequency acoustic vibrations, both theoretically and experimentally. We have implemented numerical simulations for a MOT capturing process under the presence of such instabilities, which reveals the kinematics of atoms for this scenario. Meanwhile, we have carried out experiments to test the outcome, especially by resorting to the time-of-light measurements, where acoustic vibrations are introduced to the cooling lights of MOT in a controlled manner. We demonstrate that a properly constructed MOT is robust against the low-frequency vibrations of cooling lights. Moreover, we also discuss potential applications of assessing MOT properties by the method of applying prescribed vibrations to cooling lights.
Abstract Laser cooling is used to produce ultracold atoms and molecules for quantum science and precision measurement applications. Molecules are more challenging to cool than atoms due to their vibrational and rotational internal degrees of freedom. Molecular rotations lead to the use of type-II transitions ( F ⩾ F ′ ) for magneto-optical trapping (MOT). When typical red detuned light frequencies are applied to these transitions, sub-Doppler heating is induced, resulting in higher temperatures and larger molecular cloud sizes than realized with the type-I MOTs most often used with atoms. To improve type-II MOTs, Jarvis et al (2018 Phys. Rev. Lett. 120 083201) proposed a blue-detuned MOT to be applied after initial cooling and capture with a red-detuned MOT. This was successfully implemented (Burau et al 2023 Phys. Rev. Lett. 130 193401; Jorapur et al 2024 Phys. Rev. Lett. 132 163403; Li et al 2024 Phys. Rev. Lett. 132 233402), realizing colder and denser molecular samples. Very recently, Hallas et al (2024 arXiv:2404.03636) demonstrated a blue-detuned MOT with a ‘1+2’ configuration that resulted in even stronger compression of the molecular cloud. Here, we describe and characterize theoretically the conveyor-belt mechanism that underlies this observed enhanced compression. We perform numerical simulations of the conveyor-belt mechanism using both stochastic Schrödinger equation and optical Bloch equation approaches. We investigate the conveyor-belt MOT characteristics in relation to laser parameters, g-factors and the structure of the molecule, and find that conveyor-belt trapping should be applicable to a wide range of laser-coolable molecules.
Magneto-optical traps are central to atomic and molecular quantum technologies and precision tests of fundamental physics, where both sensitivity and bandwidth scale strongly with atom number and loading rate. We demonstrate that employing multiple, closely spaced optical frequency components in the cooling light of a 87^{87}87Rb magneto-optical trap -- without utilizing any additional slowing techniques -- can double the steady state atom number and increase the loading rate by up to a factor of 4, compared to a conventional single-frequency implementation. Subsequently, we capture up to 1.0(1)×10101.0(1)\times10^{10}1.0(1)×1010 atoms with a loading rate of up to 1.3(2)×1011 atoms s−11.3(2)\times 10^{11}\,\mathrm{atoms\,s^{-1}}1.3(2)×1011atomss−1 from a thermal background. Numerical simulations reproduce the observed trends and predict substantially larger gains for increased trap sizes beyond our experimental bounds. By re-examining earlier studies of multi-frequency atom capture in the context of modern experimental hardware and emerging applications, we show that previously identified limitations can be avoided and establish multi-frequency cooling as a practical and scalable route to high-flux cold-atom sources. These results have immediate applications in portable atom-based quantum sensing, where higher bandwidth and precision can be achieved without forgoing compactness, and in atom-interferometric tests of fundamental physics, which benefit from access to larger-mass quantum systems.
A Cs-133 Magneto-Optical Trap (MOT) has been developed at the Time and Frequency Division of the Centro Nacional de Metrolog´ CENAM, in Mexico. This MOT is part of a primary frequency standard based on ultra-cold Cs atoms, called CsF-1 clock, under development at CENAM. In this Cs MOT, we use the standard configuration (ae + i ae i ) 4-horizontal 2-vertical laser beams 1.9 cm in diameter, with 5 mW each. We use a 852 nm, 5 mW, DBR laser as a master laser which is stabilized by saturation spectroscopy. Emission linewidth of the master laser is 1 MHz. In order to amplify the light of the master laser, a 50 mW, 852 nm AlGaAs laser is used as slave laser. This slave laser is stabilized by light injection technique. A 12 MHz red shift of the light is performed by two double passes through two Acusto-Optic Modulators (AOMs). The optical part of the CENAMs MOT is very robust against mechanical vibration, acoustic noise and temperature changes in our laboratory, because none of our diode lasers use an extended cavity to reduce the linewidth. In this paper, we report results of our MOT characterization as a function of several operation parameters such as the intensity of laser beams, the laser beam diameter, the red shift of light, and the gradient of the magnetic field. We also report accurate absolute measurement of the number of Cs atoms trapped in our Cs MOT. We found up to6 £ 10 7 Cs atoms trapped in our MOT measured with an uncertainty no greater than 6.4%.
The advent of the magneto-optical trap (MOT) introduced to the field of atomic physics an unprecedented surge in research opportunities and the potential for widespread application in relating fields, such as those of quantum computation, quantum optics, laser physics, and plasma physics. The MOT makes use of a process called laser cooling, whereby atoms can be manipulated through the absorption and emission of photons, in conjunction with inhomogeneous magnetic fields, to cool atoms to kinetic temperatures as low as 200 µK and contain them in a region of space. This process has given researchers a remarkable level of control and has provided the means for extensive
In cold atom physics, the complexity of traditional magneto-optical trap system limits the use of their associated instruments for field applications in atomic physics, such as gravity mapping, space navigation and deep space exploration. This study introduces a novel compact MOT design that addresses these issues by simplifying the structure and reducing the size. The height of the unit is 0.7 m, the volume is 6.3×10−2m3 and the mass is 11.32 kg. The new design utilizes a single laser to generate the two different frequencies needed for laser cooling by internally splitting the beam, shifting the frequency and then combining them, effectively controlling both the cooling and repumping beams. The compact vacuum chamber optical path, in conjunction with the magnetic field, facilitates the capture of 87Rb atoms in an ultra-high vacuum environment. Experimental results demonstrate an atom loading rate of up to 1.79×10787Rb atoms per second, confirming the system’s effectiveness in capturing and cooling 87Rb atoms. This design provides a flexible and portable solution, offering valuable insights for the advancement of compact MOT and its applications in cold atom physics.
It has been more than 30 years since the first demonstration of a magneto-optical trap (MOT) using sodium atoms. Since then the MOT has revolutionised the field of atomic physics by facilitating the emergence of a broad range of productive avenues of research using atoms prepared at low temperatures and high densities. This thesis describes the development of a novel kind of magneto-optical trap: the blue-detuned MOT. Unlike in all previous MOTs the light is blue detuned from atomic resonances and drives "type-II" transitions that have dark ground-state sub-levels. A discussion of the position-dependent and velocity-dependent forces experienced by an atom or molecule in a MOT is first used to consolidate recent theoretical work and, in particular, to introduce the concept of a blue-detuned MOT. The design and construction of an experiment that has been built to demonstrate a blue-detuned MOT using \Rb{87} is described. A thorough characterisation of this novel MOT has been performed. At high magnetic field gradients, radiation-pressure-limited densities exceeding 101110^{11}1011~cm−3^{-3}−3 have been reached whilst temperatures are cooled below 30~\si{\micro K} by the efficient and robust sub-Doppler cooling mechanisms. The maximum phase-space density measured is 6×10−66\times10^{-6}6×10−6, which is higher than in most normal atomic MOTs, comparable to the best dark SPOTs, and a million times higher than that reported for red-detuned type-II MOTs. This makes the blue-detuned MOT particularly attractive for molecules where laser cooling and trapping always uses type-II transitions. For the first time, a study of trap loss due to ultra-cold collisions between atoms occurring in the presence of near-resonant blue-detuned light is undertaken. Finally, the experiment is used to demonstrate many new and unreported configurations of MOT for \Rb{87}, showing that a comprehensive understanding of complicated MOTs is now possible, and presenting a clear direction for further research.