Conveyor-belt magneto-optical trapping of molecules
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...
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IOP Publishing
2025-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/adc032 |
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| _version_ | 1849337918669193216 |
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| author | Grace K Li Christian Hallas John M Doyle |
| author_facet | Grace K Li Christian Hallas John M Doyle |
| author_sort | Grace K Li |
| collection | DOAJ |
| description | 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 ( $F \unicode{x2A7E} F^{^{\prime}}$ ) 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. |
| format | Article |
| id | doaj-art-8bb0a8fd6f1e4254bedfcf5e2ea25850 |
| institution | Kabale University |
| issn | 1367-2630 |
| language | English |
| publishDate | 2025-01-01 |
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| series | New Journal of Physics |
| spelling | doaj-art-8bb0a8fd6f1e4254bedfcf5e2ea258502025-08-20T03:44:33ZengIOP PublishingNew Journal of Physics1367-26302025-01-0127404300210.1088/1367-2630/adc032Conveyor-belt magneto-optical trapping of moleculesGrace K Li0https://orcid.org/0000-0002-7722-3355Christian Hallas1John M Doyle2Department of Physics, Harvard University , Cambridge, MA 02138, United States of America; Harvard-MIT Center for Ultracold Atoms , Cambridge, MA 02138, United States of AmericaDepartment of Physics, Harvard University , Cambridge, MA 02138, United States of America; Harvard-MIT Center for Ultracold Atoms , Cambridge, MA 02138, United States of AmericaDepartment of Physics, Harvard University , Cambridge, MA 02138, United States of America; Harvard-MIT Center for Ultracold Atoms , Cambridge, MA 02138, United States of AmericaLaser 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 ( $F \unicode{x2A7E} F^{^{\prime}}$ ) 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.https://doi.org/10.1088/1367-2630/adc032atomic physicsmolecular physicslaser coolingmagneto-optical trappingultracold molecules |
| spellingShingle | Grace K Li Christian Hallas John M Doyle Conveyor-belt magneto-optical trapping of molecules New Journal of Physics atomic physics molecular physics laser cooling magneto-optical trapping ultracold molecules |
| title | Conveyor-belt magneto-optical trapping of molecules |
| title_full | Conveyor-belt magneto-optical trapping of molecules |
| title_fullStr | Conveyor-belt magneto-optical trapping of molecules |
| title_full_unstemmed | Conveyor-belt magneto-optical trapping of molecules |
| title_short | Conveyor-belt magneto-optical trapping of molecules |
| title_sort | conveyor belt magneto optical trapping of molecules |
| topic | atomic physics molecular physics laser cooling magneto-optical trapping ultracold molecules |
| url | https://doi.org/10.1088/1367-2630/adc032 |
| work_keys_str_mv | AT gracekli conveyorbeltmagnetoopticaltrappingofmolecules AT christianhallas conveyorbeltmagnetoopticaltrappingofmolecules AT johnmdoyle conveyorbeltmagnetoopticaltrappingofmolecules |