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

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Production of Cold Molecules in a Magneto-Optical Trap

Laurentius Windholz

Published Jan 1, 2001• 0 citations
OpenAlex

Abstract

Production of translatory cold molecules from laser-cooled atomic ensembles is reviewed. Molecules in high vibrational levels of excited potentials are generated usually via photoassociation. For production of cold ground state molecules, up to now no general scheme is known.

Related papers

Production of cold molecules in a magneto-optical trap

Laurentius Windholz

Production of translatory cold molecules from laser-cooled atomic ensembles is reviewed. Molecules in high vibrational levels of excited potentials are generated usually via photoassociation. For production of cold ground state molecules, up to now no general scheme is known.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 9, 2001•0 citations

Optical Pumping and Vibrational Cooling of Molecules

Matthieu Viteau, Amodsen Chotia, M. Allegrini +4 more

The methods producing cold molecules from cold atoms tend to leave molecular ensembles with substantial residual internal energy. For instance, cesium molecules initially formed via photoassociation of cold cesium atoms are in several vibrational levels nu of the electronic ground state. We applied a broadband femtosecond laser that redistributes the vibrational population in the ground state via a few electronic excitation/spontaneous emission cycles. The laser pulses are shaped to remove the excitation frequency band of the nu = 0 level, preventing re-excitation from that state. We observed a fast and efficient accumulation ( approximately 70% of the initially detected molecules) in the lowest vibrational level, nu = 0, of the singlet electronic state. The validity of this incoherent depopulation pumping method is very general and opens exciting prospects for laser cooling and manipulation of molecules.

arXiv:0806.3829•Science•Jul 10, 2008•278 citations

STIMULATED RAMAN MOLECULE FORMATION IN COLD ALKALI GASES.

Paul S. Julienne, Keith R. Burnett, Y. B. Band +1 more

Photoassociation is a process by which two cold, trapped atoms can be optically excited during a collision to make a vibrational level of an excited electronic state of a molecular dimer. High-resolution photoassociation spectra are now well-known for most alkali dimers. The upper level normally decays by spontaneous emission to a number of final molecular levels, bound and unbound. A laser of a second color can be used to stimulate a transition from the upper level to a particular ground state vibrational level. Such a Raman photoassociation process can be used to form translationally cold molecules in a cold atomic gas or a Bose-Einstein condensate. Coupled channels scattering calculations show that the collisional rate coefficient for coherent production of molecules in specific target states, $> 10^{-10} cm^{3}/s,$ can greatly exceed the rate coefficient for forming products due to excited state spontaneous decay. This implies the feasibility of rapid coherent conversion of atom pairs in a condensate to molecules on a time scale short compared to the trap oscillation time. The untrapped molecules can form a coherent molecular beam. We will examine the prospects for the experimental realization of photoassociative molecule formation in cold alkali gases or condensates.

•Jan 1, 1998•0 citations

Cold cesium molecules: from formation to cooling

A. Fioretti, Dimitris Sofikitis, R. Horchani +7 more

Recent experiments on formation of translationally cold ground state molecules, their subsequent broadband vibrational cooling and study of rotations are presented together with the related modeling. We produce cold molecules by photoassociating pairs of cold cesium atoms that can decay into ground state molecules in different vibrational levels. Then we laser cool the vibrational degree of freedom by selecting a single target vibrational level. Our method is based on repeated optical pumping by laser light with a spectrum broad enough to excite all populated vibrational levels but limited in its frequency bandwidth with a spatial light modulator. In such a way we are able to eliminate transitions from the selected level, in which molecules accumulate. Results for vibrational cooling into the v = 0, v = 1, v = 2 and v = 7 level of the singlet X 1Σ g ground electronic state are presented. Depletion spectroscopy is performed to study the rotational distribution of the created molecules. In the theoretical modeling of the process we are able to reproduce our results and investigate the prospects for a ‘complete’ cooling of molecules, including also their rotational degree of freedom.

Journal of Modern Optics•Aug 14, 2009•15 citations

Formation of Ultra-Cold Cs2Molecules Through Photoassociation

P. Pillet

In contrast to atoms, laser cooling of molecules is very difficult because of the lack of a closed two-level scheme for population recycling. Molecular photoassociation of cold atoms has permitted the first observation of the formation of cold ground state Cs 2 molecules. In this scheme, two free cold atoms absorb one photon, to form an electronically excited molecule in a well-defined ro-vibrational state, which yields translationally cold molecules, after spontaneous decay, in their ground state or in their lowest triplet state.

Physica Scripta•Jan 1, 2003•3 citations

Ultra-cold Molecules: Formation, Trapping and Prospects

P. Pillet, Nicolas Vanhaecke, Christian Lisdat +4 more

Different schemes for the formation of cold molecules via photoassociation are discussed. In a typical magneto-optical trap, the formation rates can reach 0.2 cold molecules per second and per atom. The measured temperatures of the cold molecular samples are in the range 10–200 µK. The possibility for accumulating the so-formed cold molecules inside a trap, or for selecting them in a well-defined level in ground state are analyzed.

Physica Scripta•Jan 1, 2003•3 citations
The methods producing cold molecules from cold atoms tend to leave molecular ensembles with substantial residual internal energy. For instance, cesium molecules initially formed via photoassociation of cold cesium atoms are in several vibrational levels nu of the electronic ground state. We applied a broadband femtosecond laser that redistributes the vibrational population in the ground state via a few electronic excitation/spontaneous emission cycles. The laser pulses are shaped to remove the excitation frequency band of the nu = 0 level, preventing re-excitation from that state. We observed a fast and efficient accumulation ( approximately 70% of the initially detected molecules) in the lowest vibrational level, nu = 0, of the singlet electronic state. The validity of this incoherent depopulation pumping method is very general and opens exciting prospects for laser cooling and manipulation of molecules.
Photoassociation is a process by which two cold, trapped atoms can be optically excited during a collision to make a vibrational level of an excited electronic state of a molecular dimer. High-resolution photoassociation spectra are now well-known for most alkali dimers. The upper level normally decays by spontaneous emission to a number of final molecular levels, bound and unbound. A laser of a second color can be used to stimulate a transition from the upper level to a particular ground state vibrational level. Such a Raman photoassociation process can be used to form translationally cold molecules in a cold atomic gas or a Bose-Einstein condensate. Coupled channels scattering calculations show that the collisional rate coefficient for coherent production of molecules in specific target states, >10−10cm3/s,> 10^{-10} cm^{3}/s,>10−10cm3/s, can greatly exceed the rate coefficient for forming products due to excited state spontaneous decay. This implies the feasibility of rapid coherent conversion of atom pairs in a condensate to molecules on a time scale short compared to the trap oscillation time. The untrapped molecules can form a coherent molecular beam. We will examine the prospects for the experimental realization of photoassociative molecule formation in cold alkali gases or condensates.
Recent experiments on formation of translationally cold ground state molecules, their subsequent broadband vibrational cooling and study of rotations are presented together with the related modeling. We produce cold molecules by photoassociating pairs of cold cesium atoms that can decay into ground state molecules in different vibrational levels. Then we laser cool the vibrational degree of freedom by selecting a single target vibrational level. Our method is based on repeated optical pumping by laser light with a spectrum broad enough to excite all populated vibrational levels but limited in its frequency bandwidth with a spatial light modulator. In such a way we are able to eliminate transitions from the selected level, in which molecules accumulate. Results for vibrational cooling into the v = 0, v = 1, v = 2 and v = 7 level of the singlet X 1Σ g ground electronic state are presented. Depletion spectroscopy is performed to study the rotational distribution of the created molecules. In the theoretical modeling of the process we are able to reproduce our results and investigate the prospects for a ‘complete’ cooling of molecules, including also their rotational degree of freedom.
In contrast to atoms, laser cooling of molecules is very difficult because of the lack of a closed two-level scheme for population recycling. Molecular photoassociation of cold atoms has permitted the first observation of the formation of cold ground state Cs 2 molecules. In this scheme, two free cold atoms absorb one photon, to form an electronically excited molecule in a well-defined ro-vibrational state, which yields translationally cold molecules, after spontaneous decay, in their ground state or in their lowest triplet state.