Physical Review Letters

Photoassociative Ionization of Heteronuclear Molecules in a Novel Two-Species Magneto-optical Trap

James P. Shaffer, Witek Chalupczak, N. P. Bigelow

Published Feb 8, 1999• 95 citations

Abstract

We describe the experimental observation of ultracold ${\mathrm{NaCs}}^{+}$ molecular formation in a novel two-species magneto-optical trap. We interpret our observations in terms of a photoassociative ionization pathway similar to that observed in a sodium trap: $\mathrm{Na}+\mathrm{Cs}+\ensuremath{\Elzxh}{\ensuremath{\omega}}_{\mathrm{Na}}+\ensuremath{\Elzxh}{\ensuremath{\omega}}_{\mathrm{Cs}}\ensuremath{\rightarrow}{\mathrm{NaCs}}^{+}{+e}^{\ensuremath{-}}$. We have directly measured the ${\mathrm{NaCs}}^{+}$ production rate as a function of the excitation laser frequency and intensity elucidating the role of ground-state hyperfine levels. We have observed resonance structures in the frequency-dependent ion rate which we associate with the molecular character of the process.

DOI: 10.1103/physrevlett.82.1124

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Ultracold collisions in a dual species 23Na-133Cs magneto-optical trap

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We present the first observation of ultracold LiCs molecules. The molecules are formed in a two-species magneto-optical trap and detected by two-photon ionization and time-of-flight mass spectrometry. The production rate coefficient is found to be in the range 10 −18 cm 3 s −1 to 10 −16 cm 3 s −1 , at least an order of magnitude smaller than for other heteronuclear diatomic molecules directly formed in a magneto-optical trap.

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Physical Review Letters

Photoassociative Ionization of Heteronuclear Molecules in a Novel Two-Species Magneto-optical Trap

James P. Shaffer, Witek Chalupczak, N. P. Bigelow

Published Feb 8, 1999• 95 citations

Publisher

Abstract

We describe the experimental observation of ultracold

{\mathrm{NaCs}}^{+}

molecular formation in a novel two-species magneto-optical trap. We interpret our observations in terms of a photoassociative ionization pathway similar to that observed in a sodium trap:

\mathrm{Na}+\mathrm{Cs}+\ensuremath{\Elzxh}{\ensuremath{\omega}}_{\mathrm{Na}}+\ensuremath{\Elzxh}{\ensuremath{\omega}}_{\mathrm{Cs}}\ensuremath{\rightarrow}{\mathrm{NaCs}}^{+}{+e}^{\ensuremath{-}}

. We have directly measured the

{\mathrm{NaCs}}^{+}

production rate as a function of the excitation laser frequency and intensity elucidating the role of ground-state hyperfine levels. We have observed resonance structures in the frequency-dependent ion rate which we associate with the molecular character of the process.

DOI: 10.1103/physrevlett.82.1124

Related papers

Observation of Ultracold Ground-State Heteronuclear Molecules

M. W. Mancini, Gustavo Deczka Telles, Anderson R. L. Caires +2 more

We report the observation of translationally ultracold heteronuclear ground-state molecules in a two-species magneto-optical trap containing 39K and 85Rb atoms. The KRb molecules are produced via photoassociation and detected by multiphoton ionization. We had characterized their temperature and measured their formation rate constant. We believe that the two-species trap could be used as a reliable source of ultracold molecules to be captured by electrostatic, magnetic, or optical traps. This possibility will certainly motivate further investigation of quantum collective effects as well as high-resolution spectroscopy of the rovibrational level structure of cold heteronuclear molecular systems.We report the observation of translationally ultracold heteronuclear ground-state molecules in a two-species magneto-optical trap containing 39K and 85Rb atoms. The KRb molecules are produced via photoassociation and detected by multiphoton ionization. We had characterized their temperature and measured their formation rate constant. We believe that the two-species trap could be used as a reliable source of ultracold molecules to be captured by electrostatic, magnetic, or optical traps. This possibility will certainly motivate further investigation of quantum collective effects as well as high-resolution spectroscopy of the rovibrational level structure of cold heteronuclear molecular systems.

Physical Review LettersApr 2, 2004163 citations

Observation of photoassociation of ultracold sodium and cesium at the asymptote Na (3S1/2) + Cs (6P1/2)

Jizhou Wu, Wenliang Liu, Xiaofeng Wang +5 more

We report on the production of ultracold heteronuclear NaCs* molecules in a dual-species magneto-optical trap through photoassociation. The electronically excited molecules are formed below the Na (3S1/2) + Cs (6P1/2) dissociation limit. 12 resonance lines are detected using trap-loss spectroscopy based on a highly sensitive modulation technique. The highest observed rovibrational level exhibits clear hyperfine structure, which is detected for the first time. This structure is simulated within a simplified model consisting of 4 coupled levels belonging to the initially unperturbed Hund’s case “a” electronic states, which have been explored in our previous work that dealt with the Na (3S1/2) + Cs (6P3/2) asymptote [W. Liu et al., Phys. Rev. A 94, 032518 (2016)].We report on the production of ultracold heteronuclear NaCs* molecules in a dual-species magneto-optical trap through photoassociation. The electronically excited molecules are formed below the Na (3S1/2) + Cs (6P1/2) dissociation limit. 12 resonance lines are detected using trap-loss spectroscopy based on a highly sensitive modulation technique. The highest observed rovibrational level exhibits clear hyperfine structure, which is detected for the first time. This structure is simulated within a simplified model consisting of 4 coupled levels belonging to the initially unperturbed Hund’s case “a” electronic states, which have been explored in our previous work that dealt with the Na (3S1/2) + Cs (6P3/2) asymptote [W. Liu et al., Phys. Rev. A 94, 032518 (2016)].

The Journal of Chemical PhysicsMay 2, 201813 citations

Ultracold collisions in a dual species 23Na-133Cs magneto-optical trap

Xu Run-Dong, Wenliang Liu, Jizhou Wu +3 more

The production and research of ultracold heteronuclear molecules have aroused the great interest recently. On the one hand, these molecules are extremely popular in experiments for exploring the collision dynamic behaviors in threshold, photoassociative spectrum and strong dipole-dipole interactions. On the other hand, ultracold polar molecules populated at deeply bound levels in the singlet ground state are the right candidates to investigate quantum memories for quantum simulation, and to study strongly interacting quantum degenerate gases. The precise knowledge of cold collision processes between two different types of alkali atoms is necessary for understanding and utilizing ultracold heteronuclear molecules, sympathetic cooling, and thus formation of two species BEC. The goal of the present investigation is to study the collisions between ultracold sodium atoms and cesium atoms. 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Photoassociation of ultracold LiRb * molecules: Observation of high efficiency and unitarity-limited rate saturation

Sourav Dutta, John Lorenz, Adeel Altaf +2 more

We report the production of ultracold heteronuclear $^{7}\mathrm{Li}^{85}\mathrm{Rb}$ molecules in excited electronic states by photoassociation (PA) of ultracold $^{7}\mathrm{Li}$ and $^{85}\mathrm{Rb}$ atoms. PA is performed in a dual-species $^{7}\mathrm{Li}$ - $^{85}\mathrm{Rb}$ magneto-optical trap (MOT) and the PA resonances are detected using trap loss spectroscopy. We identify several strong PA resonances below the Li (2 $s$ ${}^{2}$ ${S}_{1/2}$ ) + Rb (5 $p$ ${}^{2}{P}_{3/2}$ ) asymptote and experimentally determine the long range ${C}_{6}$ dispersion coefficients. We find a molecule formation rate ( ${P}_{\mathrm{LiRb}}$ ) of 3.5 \ifmmode\times\else\texttimes\fi{} 10 ${}^{7}$ s${}^{\ensuremath{-}1}$ and a PA rate coefficient ( ${K}_{\mathrm{PA}}$ ) of 1.3 \ifmmode\times\else\texttimes\fi{} 10${}^{\ensuremath{-}10}$ cm ${}^{3}$ /s, the highest among heteronuclear bi-alkali-metal molecules. At large PA laser intensity we observe the saturation of the PA rate coefficient ( ${K}_{\mathrm{PA}}$ ) close to the theoretical value at the unitarity limit.We report the production of ultracold heteronuclear $^{7}\mathrm{Li}^{85}\mathrm{Rb}$ molecules in excited electronic states by photoassociation (PA) of ultracold $^{7}\mathrm{Li}$ and $^{85}\mathrm{Rb}$ atoms. PA is performed in a dual-species $^{7}\mathrm{Li}$-$^{85}\mathrm{Rb}$ magneto-optical trap (MOT) and the PA resonances are detected using trap loss spectroscopy. We identify several strong PA resonances below the Li (2$s$ ${}^{2}$${S}_{1/2}$) + Rb (5$p$ ${}^{2}{P}_{3/2}$) asymptote and experimentally determine the long range ${C}_{6}$ dispersion coefficients. We find a molecule formation rate (${P}_{\mathrm{LiRb}}$) of 3.5 \ifmmode\times\else\texttimes\fi{} 10${}^{7}$ s${}^{\ensuremath{-}1}$ and a PA rate coefficient (${K}_{\mathrm{PA}}$) of 1.3 \ifmmode\times\else\texttimes\fi{} 10${}^{\ensuremath{-}10}$ cm${}^{3}$/s, the highest among heteronuclear bi-alkali-metal molecules. At large PA laser intensity we observe the saturation of the PA rate coefficient (${K}_{\mathrm{PA}}$) close to the theoretical value at the unitarity limit.

arXiv:1311.6297Physical Review AFeb 19, 201439 citations

Single-color photoassociative ionization of ultracold sodium: The region from 0 to -5 GHz

Arjen Amelink, K. M. Jones, Paul D. Lett +2 more

We have measured the rate of production of ${\mathrm{Na}}_{2}^{+}$ ions in collisions of ultracold Na atoms held in a magneto-optical trap (MOT) as a function of probe laser detuning using a single-color probe beam. The ion rate is measured with the atoms mainly in the $3S(f=2)$ level (``bright MOT'') or the $3S(f=1)$ level (``dark MOT''). Using recent experimental information about the doubly excited autoionizing states of ${\mathrm{Na}}_{2},$ we find that the large structures in the first 5 GHz red of the atomic transition frequency are due to a doubly resonant excitation process with levels in the ${0}_{g}^{\ensuremath{-}}$ potential (asymptotically connected to ${3S}_{1/2}{+3P}_{3/2})$ as the intermediate states, and levels in the ${0}_{u}^{\ensuremath{-}}$ and ${1}_{u}$ potentials (asymptotically connected to ${3P}_{3/2}{+3P}_{3/2})$ as the final autoionizing states. We can account for nearly all of the observed structure in this region of the spectra for both the bright and dark MOT.We have measured the rate of production of ${\mathrm{Na}}_{2}^{+}$ ions in collisions of ultracold Na atoms held in a magneto-optical trap (MOT) as a function of probe laser detuning using a single-color probe beam. The ion rate is measured with the atoms mainly in the $3S(f=2)$ level (``bright MOT'') or the $3S(f=1)$ level (``dark MOT''). Using recent experimental information about the doubly excited autoionizing states of ${\mathrm{Na}}_{2},$ we find that the large structures in the first 5 GHz red of the atomic transition frequency are due to a doubly resonant excitation process with levels in the ${0}_{g}^{\ensuremath{-}}$ potential (asymptotically connected to ${3S}_{1/2}{+3P}_{3/2})$ as the intermediate states, and levels in the ${0}_{u}^{\ensuremath{-}}$ and ${1}_{u}$ potentials (asymptotically connected to ${3P}_{3/2}{+3P}_{3/2})$ as the final autoionizing states. We can account for nearly all of the observed structure in this region of the spectra for both the bright and dark MOT.

Physical Review AJun 13, 20008 citations

We describe the experimental observation of ultracold

{\mathrm{NaCs}}^{+}

molecular formation in a novel two-species magneto-optical trap. We interpret our observations in terms of a photoassociative ionization pathway similar to that observed in a sodium trap:

\mathrm{Na}+\mathrm{Cs}+\ensuremath{\Elzxh}{\ensuremath{\omega}}_{\mathrm{Na}}+\ensuremath{\Elzxh}{\ensuremath{\omega}}_{\mathrm{Cs}}\ensuremath{\rightarrow}{\mathrm{NaCs}}^{+}{+e}^{\ensuremath{-}}

. We have directly measured the

{\mathrm{NaCs}}^{+}

We report the production of ultracold heteronuclear

^{7}\mathrm{Li}^{85}\mathrm{Rb}

molecules in excited electronic states by photoassociation (PA) of ultracold

^{7}\mathrm{Li}

and

^{85}\mathrm{Rb}

atoms. PA is performed in a dual-species

^{7}\mathrm{Li}

^{85}\mathrm{Rb}

magneto-optical trap (MOT) and the PA resonances are detected using trap loss spectroscopy. We identify several strong PA resonances below the Li (2

s

{}^{2}

{S}_{1/2}

) + Rb (5

p

{}^{2}{P}_{3/2}

) asymptote and experimentally determine the long range

{C}_{6}

dispersion coefficients. We find a molecule formation rate (

{P}_{\mathrm{LiRb}}

) of 3.5 \ifmmode\times\else\texttimes\fi{} 10

{}^{7}

s${}^{\ensuremath{-}1}$ and a PA rate coefficient (

{K}_{\mathrm{PA}}

) of 1.3 \ifmmode\times\else\texttimes\fi{} 10${}^{\ensuremath{-}10}$ cm

{}^{3}

/s, the highest among heteronuclear bi-alkali-metal molecules. At large PA laser intensity we observe the saturation of the PA rate coefficient (

{K}_{\mathrm{PA}}

) close to the theoretical value at the unitarity limit.

We have measured the rate of production of

{\mathrm{Na}}_{2}^{+}

ions in collisions of ultracold Na atoms held in a magneto-optical trap (MOT) as a function of probe laser detuning using a single-color probe beam. The ion rate is measured with the atoms mainly in the

3S(f=2)

level (``bright MOT'') or the

3S(f=1)

level (``dark MOT''). Using recent experimental information about the doubly excited autoionizing states of

{\mathrm{Na}}_{2},

we find that the large structures in the first 5 GHz red of the atomic transition frequency are due to a doubly resonant excitation process with levels in the ${0}_{g}^{\ensuremath{-}}$ potential (asymptotically connected to

{3S}_{1/2}{+3P}_{3/2})

as the intermediate states, and levels in the ${0}_{u}^{\ensuremath{-}}$ and

{1}_{u}

potentials (asymptotically connected to

{3P}_{3/2}{+3P}_{3/2})

as the final autoionizing states. We can account for nearly all of the observed structure in this region of the spectra for both the bright and dark MOT.