Physical Review A

Formation of ultracold Cs2 molecules through the double-minimum Cs2 31Σu+ state

Marin Pichler, William C. Stwalley, Robert Beuc, Goran Pichler

Published Jan 15, 2004• 12 citations

Abstract

We present a simple model of ultracold cesium dimer formation in which the photoassociation into rovibrational levels of the double-minimum ${\mathrm{Cs}}_{2}$ $3{}^{1}{\ensuremath{\Sigma}}_{u}^{+}$ state above its internal barrier enables spontaneous or stimulated emission into the lowest rovibrational levels of the ${\mathrm{Cs}}_{2}$ $1(X){}^{1}{\ensuremath{\Sigma}}_{g}^{+}$ ground electronic state. The transition dipole moment should be sufficiently large for observation of such spectral transitions. The use of the ${\mathrm{Cs}}_{2}$ $3{}^{1}{\ensuremath{\Sigma}}_{u}^{+}$ double-minimum potential could be extended to molecular Bose-Einstein condensates in which an optical trap can be employed for trapping of both atomic and molecular species.

DOI: 10.1103/physreva.69.013403

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Formation of ultracold molecules by photoassociation: theoretical developments

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Efficient formation of deeply bound ultracold molecules probed by broadband detection

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Physical Review A

Formation of ultracold Cs2 molecules through the double-minimum Cs2 31Σu+ state

Marin Pichler, William C. Stwalley, Robert Beuc, Goran Pichler

Published Jan 15, 2004• 12 citations

Publisher

Abstract

We present a simple model of ultracold cesium dimer formation in which the photoassociation into rovibrational levels of the double-minimum

{\mathrm{Cs}}_{2}

3{}^{1}{\ensuremath{\Sigma}}_{u}^{+}

state above its internal barrier enables spontaneous or stimulated emission into the lowest rovibrational levels of the

{\mathrm{Cs}}_{2}

1(X){}^{1}{\ensuremath{\Sigma}}_{g}^{+}

ground electronic state. The transition dipole moment should be sufficiently large for observation of such spectral transitions. The use of the

{\mathrm{Cs}}_{2}

3{}^{1}{\ensuremath{\Sigma}}_{u}^{+}

double-minimum potential could be extended to molecular Bose-Einstein condensates in which an optical trap can be employed for trapping of both atomic and molecular species.

DOI: 10.1103/physreva.69.013403

Related papers

Modeling optical formation of ultracold NaK 2 ground-state molecules

Baraa Shammout, Leon Karpa, Silke Ospelkaus +2 more

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Formation of ultracold molecules by photoassociation: theoretical developments

Olivier Dulieu, Françoise Masnou-Seeuws

In recent years several groups of researchers have succeeded in making samples of cold molecules, at temperatures below 1 K, and of ultracold molecules, at temperatures below 1 mK. We concentrate on the formation of Cs2 dimers. Starting with laser-cooled atoms, photoassociation forms molecules in an excited electronic state. Various mechanisms are presented for stabilizing these molecules by spontaneous emission into a bound level of the ground electronic state. The design of new formation schemes requires precise knowledge of molecular potential curves that is well beyond the accuracy of ab initio calculations. We show that analytical long-range potentials can be fitted on photoassociation spectra and yield, through the determination of the C3 long-range coefficient, a value of the radiative lifetime of the 6P3/2 cesium level with an unprecedented accuracy. For short-range potentials it is possible to avoid explicit calculations by using asymptotic methods that generalize to long-range molecules the quantum-defect concepts developed for Rydberg atoms. Considering two coupled channels, we show how generalized Lu–Fano plots can extract precise information from experimental spectra.In recent years several groups of researchers have succeeded in making samples of cold molecules, at temperatures below 1 K, and of ultracold molecules, at temperatures below 1 mK. We concentrate on the formation of Cs2 dimers. Starting with laser-cooled atoms, photoassociation forms molecules in an excited electronic state. Various mechanisms are presented for stabilizing these molecules by spontaneous emission into a bound level of the ground electronic state. The design of new formation schemes requires precise knowledge of molecular potential curves that is well beyond the accuracy of ab initio calculations. We show that analytical long-range potentials can be fitted on photoassociation spectra and yield, through the determination of the C3 long-range coefficient, a value of the radiative lifetime of the 6P3/2 cesium level with an unprecedented accuracy. For short-range potentials it is possible to avoid explicit calculations by using asymptotic methods that generalize to long-range molecules the quantum-defect concepts developed for Rydberg atoms. Considering two coupled channels, we show how generalized Lu–Fano plots can extract precise information from experimental spectra.

Journal of the Optical Society of America BMay 1, 200318 citations

Double-minimum 3 Σu+1 state in Rb2 : Spectroscopic study and possible applications for cold-physics experiments

A. Pashov, Pawel Kowalczyk, W. Jastrzȩbski

The double-minimum 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}$ state in $^{85}\mathrm{Rb}_{2}$ and $^{85}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{87}\mathrm{Rb}$ was investigated by analyzing rotationally resolved spectra of the 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}\ensuremath{\longleftarrow}\mathrm{X}^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{g}}^{+}$ band system simplified by polarization labeling. A total of 3665 transitions to rovibrational levels located in the inner well and above the internal barrier were identified and an accurate potential energy curve of the state reaching up to $R\ensuremath{\approx}21$ \AA{} was constructed using the inverted perturbation approach, making this state the best characterized double-minimum state in alkali dimers. The possibility of formation of ultracold rubidium dimers in the absolute ground state by photoassociation into levels of the 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}$ state above the internal barrier followed by spontaneous or stimulated emission is discussed.The double-minimum 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}$ state in $^{85}\mathrm{Rb}_{2}$ and $^{85}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{87}\mathrm{Rb}$ was investigated by analyzing rotationally resolved spectra of the 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}\ensuremath{\longleftarrow}\mathrm{X}^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{g}}^{+}$ band system simplified by polarization labeling. A total of 3665 transitions to rovibrational levels located in the inner well and above the internal barrier were identified and an accurate potential energy curve of the state reaching up to $R\ensuremath{\approx}21$ \AA{} was constructed using the inverted perturbation approach, making this state the best characterized double-minimum state in alkali dimers. The possibility of formation of ultracold rubidium dimers in the absolute ground state by photoassociation into levels of the 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}$ state above the internal barrier followed by spontaneous or stimulated emission is discussed.

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Production and Detection of Ultracold Ground State 85 Rb 133 Cs Molecules in the Lowest Vibrational Level by Short-Range Photoassociation

Yanting Zhao, Jinpeng Yuan, Zhonghao Li +3 more

We investigate the production of ultracold ground state X 1 σ + (v = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85 Rb and 133 Cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)0 + (v = 10) correlated to the (2) 3 π electric state is achieved by the photoassociation process. The formed ground state X 1 σ + (v = 0) molecule is resonantly excited to the 2 1 π intermediate state by a 651 nm pulse laser and is ionized by a 532 nm pulse laser and then detected by the time-of-flight mass spectrum. Saturation of the photoionization spectroscopy at large ionization laser energy is observed and the ionization efficiency is obtained from the fitting. The production of ultracold ground state 85 Rb 133 Cs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.We investigate the production of ultracold ground state X 1 σ + (v = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85 Rb and 133 Cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)0 + (v = 10) correlated to the (2) 3 π electric state is achieved by the photoassociation process. The formed ground state X 1 σ + (v = 0) molecule is resonantly excited to the 2 1 π intermediate state by a 651 nm pulse laser and is ionized by a 532 nm pulse laser and then detected by the time-of-flight mass spectrum. Saturation of the photoionization spectroscopy at large ionization laser energy is observed and the ionization efficiency is obtained from the fitting. The production of ultracold ground state 85 Rb 133 Cs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.

Chinese Physics LettersNov 1, 20153 citations

Efficient formation of deeply bound ultracold molecules probed by broadband detection

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

Using a nonselective broadband detection scheme we discovered an efficient mechanism of formation of ultracold ${\mathrm{Cs}}_{2}$ molecules in deeply bound vibrational levels $(v=1--9)$ of their electronic ground state $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$. They are formed by a one-photon photoassociation of ultracold cesium atoms in a manifold of excited electronic states, followed by a two-step spontaneous emission cascade. This process creates about ${10}^{5}--{10}^{6}\phantom{\rule{0.3em}{0ex}}\text{molecules}\phantom{\rule{0.3em}{0ex}}\text{per}\phantom{\rule{0.3em}{0ex}}\text{second}$ . This detection scheme is an advancement compare to previous ones and could be generalized to other molecular species for the systematic investigation of cold molecule formation mechanisms.Using a nonselective broadband detection scheme we discovered an efficient mechanism of formation of ultracold ${\mathrm{Cs}}_{2}$ molecules in deeply bound vibrational levels $(v=1--9)$ of their electronic ground state $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$. They are formed by a one-photon photoassociation of ultracold cesium atoms in a manifold of excited electronic states, followed by a two-step spontaneous emission cascade. This process creates about ${10}^{5}--{10}^{6}\phantom{\rule{0.3em}{0ex}}\text{molecules}\phantom{\rule{0.3em}{0ex}}\text{per}\phantom{\rule{0.3em}{0ex}}\text{second}$. This detection scheme is an advancement compare to previous ones and could be generalized to other molecular species for the systematic investigation of cold molecule formation mechanisms.

arXiv:0809.4991Physical Review AFeb 18, 200929 citations

We present a simple model of ultracold cesium dimer formation in which the photoassociation into rovibrational levels of the double-minimum

{\mathrm{Cs}}_{2}

3{}^{1}{\ensuremath{\Sigma}}_{u}^{+}

state above its internal barrier enables spontaneous or stimulated emission into the lowest rovibrational levels of the

{\mathrm{Cs}}_{2}

1(X){}^{1}{\ensuremath{\Sigma}}_{g}^{+}

ground electronic state. The transition dipole moment should be sufficiently large for observation of such spectral transitions. The use of the

{\mathrm{Cs}}_{2}

3{}^{1}{\ensuremath{\Sigma}}_{u}^{+}

double-minimum potential could be extended to molecular Bose-Einstein condensates in which an optical trap can be employed for trapping of both atomic and molecular species.

The double-minimum 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}$ state in

^{85}\mathrm{Rb}_{2}

and

^{85}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{87}\mathrm{Rb}

was investigated by analyzing rotationally resolved spectra of the 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}\ensuremath{\longleftarrow}\mathrm{X}^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{g}}^{+}$ band system simplified by polarization labeling. A total of 3665 transitions to rovibrational levels located in the inner well and above the internal barrier were identified and an accurate potential energy curve of the state reaching up to $R\ensuremath{\approx}21$ \AA{} was constructed using the inverted perturbation approach, making this state the best characterized double-minimum state in alkali dimers. The possibility of formation of ultracold rubidium dimers in the absolute ground state by photoassociation into levels of the 3 $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}+}$ state above the internal barrier followed by spontaneous or stimulated emission is discussed.

Using a nonselective broadband detection scheme we discovered an efficient mechanism of formation of ultracold

{\mathrm{Cs}}_{2}

molecules in deeply bound vibrational levels

(v=1--9)

of their electronic ground state $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$. They are formed by a one-photon photoassociation of ultracold cesium atoms in a manifold of excited electronic states, followed by a two-step spontaneous emission cascade. This process creates about

{10}^{5}--{10}^{6}\phantom{\rule{0.3em}{0ex}}\text{molecules}\phantom{\rule{0.3em}{0ex}}\text{per}\phantom{\rule{0.3em}{0ex}}\text{second}

. This detection scheme is an advancement compare to previous ones and could be generalized to other molecular species for the systematic investigation of cold molecule formation mechanisms.