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

arXiv:physics/0212022 · Physical Review A

Photoassociation spectroscopy of cold calcium atoms

C. Degenhardt, T. Binnewies, G. Wilpers, Uwe Sterr, F. Riehle, Christian Lisdat, E. Tiemann

Published Apr 22, 2003• 46 citations
arXivHTMLPDF

Abstract

Photoassociation spectroscopy experiments on ${}^{40}\mathrm{Ca}$ atoms close to the dissociation limit ${4s4s}^{1}{S}_{0}\ensuremath{-}{4s4p}^{1}{P}_{1}$ are presented. The vibronic spectrum was measured for detunings of the photoassociation laser ranging from 0.6 to 68 GHz with respect to the atomic resonance. In contrast to previous measurements, the rotational splitting of the vibrational lines was fully resolved. Full quantum-mechanical numerical simulations of the photoassociation spectrum were performed which allowed us to put constraints on the possible range of the calcium scattering length between ${50a}_{0}$ and ${300a}_{0}.$

DOI
10.1103/physreva.67.043408

Related papers

Photoassociation Spectroscopy of Laser-Cooled Ytterbium Atoms

洋介 高須, Yosuke Takasu, 和仁 本多 +8 more

We report the photoassociation spectroscopy of laser-cooled ytterbium atoms in an optical trap. We observed more than 90 photoassociation resonances of vibrational levels in the 1Σu+ state, including 80 consecutive series, up to 490 GHz detuning with respect to the atomic resonance. From the resonance frequencies we derived the atomic radiative lifetime of the (6s6p) 1P1 state to be 5.464±0.005 ns, which is about 2 orders of magnitude improvement over previous results. We also observed line broadening of resonances, which is ascribed to the predissociation to the triplet states, and estimated the transition probability to be 0.2. Furthermore, we observed the decrease of the photoassociation signal intensity, from which the scattering length is estimated to be equal to or less than 3 nm.

•Sep 1, 2003•0 citations

Photoassociation spectroscopy of Ca40 measured with kilohertz accuracy near the 3P1+1S0 asymptote and its Zeeman effect

Max Kahmann, E. Tiemann, Oliver Appel +2 more

We report on measurements of narrow photoassociation lines of $^{40}\mathrm{Ca}$ near the ${}^{3}{P}_{1}$ + ${}^{1}{S}_{0}$ asymptote related to the molecular states ${}^{3}{\ensuremath{\Pi}}_{u}$ and ${}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ at about 1 $\ensuremath{\mu}$K. From the measured binding energies an accurate description of the long-range interaction potentials was obtained; it was found to be crucial to also include the precisely measured molecular Zeeman splittings. Our analysis is a first step towards application of optical Feshbach resonances in $^{40}\mathrm{Ca}$ to modify the scattering length significantly with small losses.

Physical Review A•Feb 12, 2014•8 citations

Photoassociation of Cold Ca Atoms

G. Zinner, T. Binnewies, F. Riehle +1 more

We present the first measurement of a photoassociative spectrum of an alkaline earth element near the dissociation limit. The observed spectrum of Ca2 formed from cold atoms shows the regular vibrational series with the characteristic spacing of the 1/R3 asymptotic potential. The interpretation is in principle simplified compared to previous measurements on alkali metals by the nondegenerate ground state and the missing hyperfine structure of 40Ca. As an example, we derive the natural decay rate of the excited atomic 4p 1P1 state from the positions of the observed vibrational and rotational resonances with reduced uncertainty compared to previous measurements.

Physical Review Letters•Sep 11, 2000•114 citations

Photoassociation Spectroscopy of Laser-Cooled Ytterbium Atoms

Yosuke Takasu, Kaduki Komori, Keita HONDA +3 more

We report the photoassociation spectroscopy of laser-cooled ytterbium atoms in an optical trap. We observed more than 90 photoassociation resonances of vibrational levels in the (1)Sigma(+)(u) state, including 80 consecutive series, up to 490 GHz detuning with respect to the atomic resonance. From the resonance frequencies we derived the atomic radiative lifetime of the (6s6p) 1P1 state to be 5.464+/-0.005 ns, which is about 2 orders of magnitude improvement over previous results. We also observed line broadening of resonances, which is ascribed to the predissociation to the triplet states, and estimated the transition probability to be 0.2. Furthermore, we observed the decrease of the photoassociation signal intensity, from which the scattering length is estimated to be equal to or less than 3 nm.

Physical Review Letters•Sep 15, 2004•73 citations

Photoassociation of 40Ca at high laser intensities

Veit Peter Dahlke

In this thesis I present the results of photoassociation measurements in ensembles of atomic calcium over an intensity range of below 1 W/cm2 up to 600 W/cm2. The temperature of the atoms was reduced to 1 μK by laser and evaporative cooling. Afterwards the two most-weakly bound states in the excited molecular potentials that dissociate to the asymtote 3P1+1S0 have been investigated regarding the shape and absolute rate of the resonances. The investigation showed that the measured rates differ by more than an order of magnitude compared to theoretical calculations. The predictions are based on a scattering formalism by Bohn & Julienne and wave functions derived from coupled-channel calculations. The shape of the resonances, the width in particular, agrees well with the numerical calculations. Especially the power broadening at high intensity is reproduced by the experiment. Further the light shift introduced by the photoassociation laser has been measured which also differs from the predictions. In the further course of the thesis the numerical simulations were improved by considering additional influences like the exact dependence of the Franck-Condon density and the light shift of the photoassociation laser as a function of the collision energy. Additionally the modeling of the experimental setup with a special emphasis on the volume of the optical trap and thus the density of the atomic ensemble was improved and the influence of varying trap depth and photoassociation duration has been studied. Investigating possible explanations for the discrepancy of the measured rates compared to theory, I show that by a modification of the coupling parameter and the spontaneous decay rate of the molecular state the rates measured in the experiment can be reproduced theoretically, with the restriction that at high intensity the calculated line shape no longer agrees with the measurement. In the last chapter an improved experimental apparatus is presented that by using an optical lattice suppresses thermal broadening and thus simplifies the analysis substantially.

•Jan 1, 2020•0 citations

Ground-state properties of Ca2 from narrow-line two-color photoassociation

Evgenij Pachomow, Veit Peter Dahlke, E. Tiemann +2 more

By two-color photoassociation of $^{40}\mathrm{Ca}$ four weakly bound vibrational levels in the ${\mathrm{Ca}}_{2} X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ ground-state potential were measured, using highly spin-forbidden transitions to intermediate states of the coupled system ${^{3}\mathrm{\ensuremath{\Pi}}}_{u}$ and ${^{3}\mathrm{\ensuremath{\Sigma}}}_{u}^{+}$ near the ${^{3}P}_{1}+{^{1}S}_{0}$ asymptote. From the observed binding energies, including the least bound state, the long-range dispersion coefficients ${\mathrm{C}}_{6},{\mathrm{C}}_{8},{\mathrm{C}}_{10}$ and a precise value for the $s$-wave scattering length of 308.5(50)${a}_{0}$ were derived. From mass scaling we also calculated the corresponding scattering length for other natural isotopes. From the Autler-Townes splitting of the spectra, the molecular Rabi frequency has been determined as a function of the laser intensity for one bound-bound transition. The observed value for the Rabi frequency is in good agreement with calculated transition moments based on the derived potentials, assuming a dipole moment being independent of internuclear separation for the atomic pair model.

arXiv:1702.00710•Physical Review A•Apr 25, 2017•14 citations
Photoassociation spectroscopy experiments on 40Ca{}^{40}\mathrm{Ca}40Ca atoms close to the dissociation limit 4s4s1S0\ensuremath−4s4p1P1{4s4s}^{1}{S}_{0}\ensuremath{-}{4s4p}^{1}{P}_{1}4s4s1S0​\ensuremath−4s4p1P1​ are presented. The vibronic spectrum was measured for detunings of the photoassociation laser ranging from 0.6 to 68 GHz with respect to the atomic resonance. In contrast to previous measurements, the rotational splitting of the vibrational lines was fully resolved. Full quantum-mechanical numerical simulations of the photoassociation spectrum were performed which allowed us to put constraints on the possible range of the calcium scattering length between 50a0{50a}_{0}50a0​ and 300a0.{300a}_{0}.300a0​.
We report the photoassociation spectroscopy of laser-cooled ytterbium atoms in an optical trap. We observed more than 90 photoassociation resonances of vibrational levels in the 1Σu+ state, including 80 consecutive series, up to 490 GHz detuning with respect to the atomic resonance. From the resonance frequencies we derived the atomic radiative lifetime of the (6s6p) 1P1 state to be 5.464±0.005 ns, which is about 2 orders of magnitude improvement over previous results. We also observed line broadening of resonances, which is ascribed to the predissociation to the triplet states, and estimated the transition probability to be 0.2. Furthermore, we observed the decrease of the photoassociation signal intensity, from which the scattering length is estimated to be equal to or less than 3 nm.
We report on measurements of narrow photoassociation lines of 40Ca^{40}\mathrm{Ca}40Ca near the 3P1{}^{3}{P}_{1}3P1​ + 1S0{}^{1}{S}_{0}1S0​ asymptote related to the molecular states ${}^{3}{\ensuremath{\Pi}}_{u}$ and ${}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ at about 1 $\ensuremath{\mu}$K. From the measured binding energies an accurate description of the long-range interaction potentials was obtained; it was found to be crucial to also include the precisely measured molecular Zeeman splittings. Our analysis is a first step towards application of optical Feshbach resonances in 40Ca^{40}\mathrm{Ca}40Ca to modify the scattering length significantly with small losses.
We present the first measurement of a photoassociative spectrum of an alkaline earth element near the dissociation limit. The observed spectrum of Ca2 formed from cold atoms shows the regular vibrational series with the characteristic spacing of the 1/R3 asymptotic potential. The interpretation is in principle simplified compared to previous measurements on alkali metals by the nondegenerate ground state and the missing hyperfine structure of 40Ca. As an example, we derive the natural decay rate of the excited atomic 4p 1P1 state from the positions of the observed vibrational and rotational resonances with reduced uncertainty compared to previous measurements.
We report the photoassociation spectroscopy of laser-cooled ytterbium atoms in an optical trap. We observed more than 90 photoassociation resonances of vibrational levels in the (1)Sigma(+)(u) state, including 80 consecutive series, up to 490 GHz detuning with respect to the atomic resonance. From the resonance frequencies we derived the atomic radiative lifetime of the (6s6p) 1P1 state to be 5.464+/-0.005 ns, which is about 2 orders of magnitude improvement over previous results. We also observed line broadening of resonances, which is ascribed to the predissociation to the triplet states, and estimated the transition probability to be 0.2. Furthermore, we observed the decrease of the photoassociation signal intensity, from which the scattering length is estimated to be equal to or less than 3 nm.
In this thesis I present the results of photoassociation measurements in ensembles of atomic calcium over an intensity range of below 1 W/cm2 up to 600 W/cm2. The temperature of the atoms was reduced to 1 μK by laser and evaporative cooling. Afterwards the two most-weakly bound states in the excited molecular potentials that dissociate to the asymtote 3P1+1S0 have been investigated regarding the shape and absolute rate of the resonances. The investigation showed that the measured rates differ by more than an order of magnitude compared to theoretical calculations. The predictions are based on a scattering formalism by Bohn & Julienne and wave functions derived from coupled-channel calculations. The shape of the resonances, the width in particular, agrees well with the numerical calculations. Especially the power broadening at high intensity is reproduced by the experiment. Further the light shift introduced by the photoassociation laser has been measured which also differs from the predictions. In the further course of the thesis the numerical simulations were improved by considering additional influences like the exact dependence of the Franck-Condon density and the light shift of the photoassociation laser as a function of the collision energy. Additionally the modeling of the experimental setup with a special emphasis on the volume of the optical trap and thus the density of the atomic ensemble was improved and the influence of varying trap depth and photoassociation duration has been studied. Investigating possible explanations for the discrepancy of the measured rates compared to theory, I show that by a modification of the coupling parameter and the spontaneous decay rate of the molecular state the rates measured in the experiment can be reproduced theoretically, with the restriction that at high intensity the calculated line shape no longer agrees with the measurement. In the last chapter an improved experimental apparatus is presented that by using an optical lattice suppresses thermal broadening and thus simplifies the analysis substantially.
By two-color photoassociation of 40Ca^{40}\mathrm{Ca}40Ca four weakly bound vibrational levels in the ${\mathrm{Ca}}_{2} X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ ground-state potential were measured, using highly spin-forbidden transitions to intermediate states of the coupled system ${^{3}\mathrm{\ensuremath{\Pi}}}_{u}$ and ${^{3}\mathrm{\ensuremath{\Sigma}}}_{u}^{+}$ near the 3P1+1S0{^{3}P}_{1}+{^{1}S}_{0}3P1​+1S0​ asymptote. From the observed binding energies, including the least bound state, the long-range dispersion coefficients C6,C8,C10{\mathrm{C}}_{6},{\mathrm{C}}_{8},{\mathrm{C}}_{10}C6​,C8​,C10​ and a precise value for the sss-wave scattering length of 308.5(50)a0{a}_{0}a0​ were derived. From mass scaling we also calculated the corresponding scattering length for other natural isotopes. From the Autler-Townes splitting of the spectra, the molecular Rabi frequency has been determined as a function of the laser intensity for one bound-bound transition. The observed value for the Rabi frequency is in good agreement with calculated transition moments based on the derived potentials, assuming a dipole moment being independent of internuclear separation for the atomic pair model.