Physical Review A

Photoassociative ionization using two independent colors in a sodium-vapor-cell magneto-optical traps

Luís Gustavo Marcassa, Gustavo Deczka Telles, Sérgio Ricardo Muniz

Published Aug 1, 1999• 0 citations

Abstract

We present an extended experimental investigation of the photoassociative ionization process involving ultracold atoms. Different steps of this collisional process can be studied in detail using two independent laser frequencies. The experimental results are compared with a simple local equilibrium theory. This work complements our previous work [Phys. Rev. Lett. 70, 3225 (1993)], showing that the main physical insights of the process can be reproduced with a semiclassical theory.

DOI: 10.1103/physreva.60.1305

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Physical Review A

Photoassociative ionization using two independent colors in a sodium-vapor-cell magneto-optical traps

Luís Gustavo Marcassa, Gustavo Deczka Telles, Sérgio Ricardo Muniz

Published Aug 1, 1999• 0 citations

Publisher

Abstract

DOI: 10.1103/physreva.60.1305

Related papers

Photo-associative ionization in ultracold sodium atoms

Vanderlei Salvador Bagnato, Luís Gustavo Marcassa, Chia‐Wen Tsao +2 more

We study photo-associative ionization (PAI) for sodium atoms held in a magneto-optical trap (T < 1 mK). The process is investigated using one and two laser frequencies. For a single color PAI, we measure the rate constant as a function of light intensity and the result is compared with calculation based on semiclassical Bloch equation theory. The measured rate constant appears to saturate sooner than theory. In the two-color PAI (TCPAI) we investigate individual steps of the process. Different combinations of laser frequencies prepare different populations in each of the hyperfine ground state and the contribution of each one in this collisional process is investigated. The comparison with theory allows a fairly clear understanding of PAI and TCPAI.We study photo-associative ionization (PAI) for sodium atoms held in a magneto-optical trap (T < 1 mK). The process is investigated using one and two laser frequencies. For a single color PAI, we measure the rate constant as a function of light intensity and the result is compared with calculation based on semiclassical Bloch equation theory. The measured rate constant appears to saturate sooner than theory. In the two-color PAI (TCPAI) we investigate individual steps of the process. Different combinations of laser frequencies prepare different populations in each of the hyperfine ground state and the contribution of each one in this collisional process is investigated. The comparison with theory allows a fairly clear understanding of PAI and TCPAI.

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

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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

Optical Suppression of Photoassociative Ionization in a Magneto-Optical Trap

Luís Gustavo Marcassa, Sérgio Ricardo Muniz, E Queiroz +5 more

Physical Review LettersOct 3, 199461 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}}^{+}

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.

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.