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

Physics World

Triatomic molecules laser-cooled

Published Jun 1, 2017• 0 citations
Publisher

Abstract

Molecules containing three atoms have been laser-cooled to ultracold temperatures for the first time. John Doyle and colleagues at Harvard University in the US used a technique called Sisyphus cooling to chill an ensemble of about a million strontium-monohydroxide molecules to 750 μK.
DOI
10.1088/2058-7058/30/6/5

Related papers

Sisyphus Laser Cooling of a Polyatomic Molecule

Ivan Kozyryev, Louis Baum, Kyle Matsuda +4 more

We perform magnetically assisted Sisyphus laser cooling of the triatomic free radical strontium monohydroxide (SrOH). This is achieved with principal optical cycling in the rotationally closed P(N^{''}=1) branch of either the X[over ˜]^{2}Σ^{+}(000)↔A[over ˜]^{2}Π_{1/2}(000) or the X[over ˜]^{2}Σ^{+}(000)↔B[over ˜]^{2}Σ^{+}(000) vibronic transitions. Molecules lost into the excited vibrational states during the cooling process are repumped back through the B[over ˜](000) state for both the (100) level of the Sr-O stretching mode and the (02^{0}0) level of the bending mode. The transverse temperature of a SrOH molecular beam is reduced in one dimension by 2 orders of magnitude to ∼750 μK. This approach opens a path towards creating a variety of ultracold polyatomic molecules by means of direct laser cooling.

arXiv:1609.02254•Physical Review Letters•Apr 24, 2017•259 citations

Laser Cooling and Slowing of a Diatomic Molecule

John F. Barry

Laser cooling and trapping are central to modern atomic physics. It has been roughly three decades since laser cooling techniques produced ultracold atoms, leading to rapid advances in a vast array of fields and a number of Nobel prizes. Prior to the work presented in this thesis, laser cooling had not yet been extended to molecules because of their complex internal structure. However, this complexity makes molecules potentially useful for a wide range of applications. The first direct laser cooling of a molecule and further results we present here provide a new route to ultracold temperatures for molecules. In particular, these methods bridge the gap between ultracold temperatures and the approximately 1 kelvin temperatures attainable with directly cooled molecules (e.g. with cryogenic buffer gas cooling or decelerated supersonic beams). Using the carefully chosen molecule strontium monofluoride (SrF), decays to unwanted vibrational states are suppressed. Driving a transition with rotational quantum number R=1 to an excited state with R'=0 eliminates decays to unwanted rotational states. The dark ground-state Zeeman sublevels present in this specific scheme are remixed via a static magnetic field. Using three lasers for this scheme, a given molecule should undergo an average of approximately 100,000 photon absorption/emission cycles before being lost via unwanted decays. This number of cycles should be sufficient to load a magneto-optical trap (MOT) of molecules. In this thesis, we demonstrate transverse cooling of an SrF beam, in both Doppler and a Sisyphus-type cooling regimes. We also realize longitudinal slowing of an SrF beam. Finally, we detail current progress towards trapping SrF in a MOT. Ultimately, this technique should enable the production of large samples of molecules at ultracold temperatures for molecules chemically distinct from competing methods.

•Dec 1, 2013•21 citations

A Diatomic Molecule is One Atom too Few

Paul Hamilton, Eric R. Hudson

We perform magnetically assisted Sisyphus laser cooling of the triatomic free radical strontium monohydroxide (SrOH).This is achieved with principal optical cycling in the rotationally closed PðN 00 ¼ 1Þ branch of either the X2 Σ þ ð000Þ ↔ Ã2 Π 1=2 ð000Þ or the X2 Σ þ ð000Þ ↔ B2 Σ þ ð000Þ vibronic transitions.Molecules lost into the excited vibrational states during the cooling process are repumped back through the Bð000Þ state for both the (100) level of the Sr-O stretching mode and the ð02 0 0Þ level of the bending mode.The transverse temperature of a SrOH molecular beam is reduced in one dimension by 2 orders of magnitude to ∼750 μK.This approach opens a path towards creating a variety of ultracold polyatomic molecules by means of direct laser cooling.

Physics•Apr 24, 2017•0 citations

Methods for Direct Laser Cooling of Polyatomic Molecules

Benjamin L. Augenbraun

Molecules controlled at the single-quantum-state level offer wide-ranging applications spanning many of the frontiers of modern physics. Within the past decade, simple diatomic molecules have been brought under full quantum control both via assembly from pre-cooled atoms and by direct laser cooling. Polyatomic molecules\footnote{Molecules that contain three or more atoms.} have attracted focus as novel quantum resources providing distinct advantages (and challenges) compared to both atoms and diatomic molecules. For example, nearly all polyatomic molecules have long-lived states that can be fully polarized at low applied electric fields. These and other features generic to polyatomic molecules can be applied to quantum simulation, quantum chemistry, and tests of fundamental physics beyond the Standard Model. While these structural features of polyatomic molecules are highly promising for applications, they complicate the process of bringing molecules under full quantum control. In this thesis, we describe a series of experimental and theoretical advances toward the production of ultracold complex polyatomic molecules. We demonstrate the first laser cooling of the polyatomic radical ytterbium monohydroxide (YbOH), a promising candidate to search for particles and interactions beyond the Standard Model of particle physics. We develop a novel deceleration technique (``Zeeman-Sisyphus deceleration") capable of slowing molecular beams to trappable velocities while scattering fewer than 10 optical photons. This deceleration method is demonstrated using CaOH molecules, a lighter analog of YbOH. In order to determine a viable pathway to full three-dimensional cooling and trapping of YbOH, we develop a spectroscopic technique to measure vibrational branching ratios with relative intensity sensitivity around 1 part in $10^5$, approximately two orders of magnitude beyond the previous state of the art. We also perform the first spectroscopic observations and characterizations of the related molecule ytterbium monomethoxide, YbOCH$_3$, a promising species to probe beyond-the-Standard-Model physics. In addition, we show theoretically that an entire class of asymmetric top molecules can be laser cooled using essentially the same techniques used for much simpler species. Measurements of the vibrational branching ratios for a few prototypical asymmetric to molecules (CaSH and CaNH$_2$) are presented to confirm these predictions.

•Jan 1, 2022•0 citations

Laser-coolable polyatomic molecules with heavy nuclei

T A Isaev, Andrei V. Zaitsevskii, E Eliav

Abstract Recently, a few diatomic and polyatomic molecules have been identified as prospective systems for Doppler/Sisyphus cooling. Doppler/Sisyphus cooling allows us to decrease the kinetic energy of molecules down to μ K temperatures with high efficiency and allows their capture in molecular traps, including magneto-optical traps. Trapped molecules can be used for creating molecular fountains and/or performing controlled chemical reactions, high-precision spectra measurements, and a wealth of other applications. Polyatomic molecules with heavy nuclei are of considerable interest for the ‘new physics’ search outside of the Standard Model and other applications including cold chemistry and photochemistry, quantum informatics, etc. Here, we focus on the radium monohydroxide molecule (RaOH), which is on the one hand amenable to laser cooling and on the other hand opens excellent possibilities for  -odd and  ,  -odd effects research. At present, RaOH is the heaviest polyatomic molecule proposed for direct cooling with lasers.

arXiv:1610.08243•Journal of Physics B Atomic Molecular and Optical Physics•Sep 26, 2017•91 citations

Light Gives Molecules the Chills

Adela Marian, Břetislav Friedrich

A Sisyphean task: Laser cooling of molecules is difficult, mainly due to their rich vibrational structure, typically requiring dozens of repumping lasers. However, a proof-of-principle experiment to laser cool SrF molecules has been done (see picture), showing that laser cooling of some molecules is possible with just three lasers, as Highlighted herein.

ChemPhysChem•Jan 4, 2011•1 citation
We perform magnetically assisted Sisyphus laser cooling of the triatomic free radical strontium monohydroxide (SrOH). This is achieved with principal optical cycling in the rotationally closed P(N^{''}=1) branch of either the X[over ˜]^{2}Σ^{+}(000)↔A[over ˜]^{2}Π_{1/2}(000) or the X[over ˜]^{2}Σ^{+}(000)↔B[over ˜]^{2}Σ^{+}(000) vibronic transitions. Molecules lost into the excited vibrational states during the cooling process are repumped back through the B[over ˜](000) state for both the (100) level of the Sr-O stretching mode and the (02^{0}0) level of the bending mode. The transverse temperature of a SrOH molecular beam is reduced in one dimension by 2 orders of magnitude to ∼750 μK. This approach opens a path towards creating a variety of ultracold polyatomic molecules by means of direct laser cooling.
Laser cooling and trapping are central to modern atomic physics. It has been roughly three decades since laser cooling techniques produced ultracold atoms, leading to rapid advances in a vast array of fields and a number of Nobel prizes. Prior to the work presented in this thesis, laser cooling had not yet been extended to molecules because of their complex internal structure. However, this complexity makes molecules potentially useful for a wide range of applications. The first direct laser cooling of a molecule and further results we present here provide a new route to ultracold temperatures for molecules. In particular, these methods bridge the gap between ultracold temperatures and the approximately 1 kelvin temperatures attainable with directly cooled molecules (e.g. with cryogenic buffer gas cooling or decelerated supersonic beams). Using the carefully chosen molecule strontium monofluoride (SrF), decays to unwanted vibrational states are suppressed. Driving a transition with rotational quantum number R=1 to an excited state with R'=0 eliminates decays to unwanted rotational states. The dark ground-state Zeeman sublevels present in this specific scheme are remixed via a static magnetic field. Using three lasers for this scheme, a given molecule should undergo an average of approximately 100,000 photon absorption/emission cycles before being lost via unwanted decays. This number of cycles should be sufficient to load a magneto-optical trap (MOT) of molecules. In this thesis, we demonstrate transverse cooling of an SrF beam, in both Doppler and a Sisyphus-type cooling regimes. We also realize longitudinal slowing of an SrF beam. Finally, we detail current progress towards trapping SrF in a MOT. Ultimately, this technique should enable the production of large samples of molecules at ultracold temperatures for molecules chemically distinct from competing methods.
We perform magnetically assisted Sisyphus laser cooling of the triatomic free radical strontium monohydroxide (SrOH).This is achieved with principal optical cycling in the rotationally closed PðN 00 ¼ 1Þ branch of either the X2 Σ þ ð000Þ ↔ Ã2 Π 1=2 ð000Þ or the X2 Σ þ ð000Þ ↔ B2 Σ þ ð000Þ vibronic transitions.Molecules lost into the excited vibrational states during the cooling process are repumped back through the Bð000Þ state for both the (100) level of the Sr-O stretching mode and the ð02 0 0Þ level of the bending mode.The transverse temperature of a SrOH molecular beam is reduced in one dimension by 2 orders of magnitude to ∼750 μK.This approach opens a path towards creating a variety of ultracold polyatomic molecules by means of direct laser cooling.
Molecules controlled at the single-quantum-state level offer wide-ranging applications spanning many of the frontiers of modern physics. Within the past decade, simple diatomic molecules have been brought under full quantum control both via assembly from pre-cooled atoms and by direct laser cooling. Polyatomic molecules\footnote{Molecules that contain three or more atoms.} have attracted focus as novel quantum resources providing distinct advantages (and challenges) compared to both atoms and diatomic molecules. For example, nearly all polyatomic molecules have long-lived states that can be fully polarized at low applied electric fields. These and other features generic to polyatomic molecules can be applied to quantum simulation, quantum chemistry, and tests of fundamental physics beyond the Standard Model. While these structural features of polyatomic molecules are highly promising for applications, they complicate the process of bringing molecules under full quantum control. In this thesis, we describe a series of experimental and theoretical advances toward the production of ultracold complex polyatomic molecules. We demonstrate the first laser cooling of the polyatomic radical ytterbium monohydroxide (YbOH), a promising candidate to search for particles and interactions beyond the Standard Model of particle physics. We develop a novel deceleration technique (``Zeeman-Sisyphus deceleration") capable of slowing molecular beams to trappable velocities while scattering fewer than 10 optical photons. This deceleration method is demonstrated using CaOH molecules, a lighter analog of YbOH. In order to determine a viable pathway to full three-dimensional cooling and trapping of YbOH, we develop a spectroscopic technique to measure vibrational branching ratios with relative intensity sensitivity around 1 part in 10510^5105, approximately two orders of magnitude beyond the previous state of the art. We also perform the first spectroscopic observations and characterizations of the related molecule ytterbium monomethoxide, YbOCH3_33​, a promising species to probe beyond-the-Standard-Model physics. In addition, we show theoretically that an entire class of asymmetric top molecules can be laser cooled using essentially the same techniques used for much simpler species. Measurements of the vibrational branching ratios for a few prototypical asymmetric to molecules (CaSH and CaNH2_22​) are presented to confirm these predictions.
Abstract Recently, a few diatomic and polyatomic molecules have been identified as prospective systems for Doppler/Sisyphus cooling. Doppler/Sisyphus cooling allows us to decrease the kinetic energy of molecules down to μ K temperatures with high efficiency and allows their capture in molecular traps, including magneto-optical traps. Trapped molecules can be used for creating molecular fountains and/or performing controlled chemical reactions, high-precision spectra measurements, and a wealth of other applications. Polyatomic molecules with heavy nuclei are of considerable interest for the ‘new physics’ search outside of the Standard Model and other applications including cold chemistry and photochemistry, quantum informatics, etc. Here, we focus on the radium monohydroxide molecule (RaOH), which is on the one hand amenable to laser cooling and on the other hand opens excellent possibilities for  -odd and  ,  -odd effects research. At present, RaOH is the heaviest polyatomic molecule proposed for direct cooling with lasers.