Optics Letters

Laser cooling and isotope separation of Cd^+ ions confined in a linear Paul trap

U. Tanaka, Hidetsuka Imajo, Kazuhiro Hayasaka, R. Ohmukai, Masayoshi Watanabe, Shinji Urabe

Published Sep 1, 1997• 11 citations

Abstract

Cadmium ions in a natural isotope mixture have been trapped in a linear Paul trap and laser cooled. The fluorescence spectra from all even isotopes, including the (108)Cd(+) isotopes with a natural abundance of 0.89%, were observed. Additionally, we eliminated the heavier isotopes from the trapping region by adjusting the tuning of the laser frequency and by changing the dc voltage applied to the end electrodes.

DOI: 10.1364/ol.22.001353

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Optics Letters

Laser cooling and isotope separation of Cd^+ ions confined in a linear Paul trap

U. Tanaka, Hidetsuka Imajo, Kazuhiro Hayasaka, R. Ohmukai, Masayoshi Watanabe, Shinji Urabe

Published Sep 1, 1997• 11 citations

Publisher

Abstract

DOI: 10.1364/ol.22.001353

Related papers

High-resolution ultraviolet spectra of sympathetically-laser-cooled Cd+ ions

Hidetsuka Imajo, Kazuhiro Hayasaka, R. Ohmukai +3 more

Cadmium ions ( ${\mathrm{Cd}}^{+}$ ) have been cooled sympathetically below 1 K by means of Coulomb interactions with laser-cooled ${\mathrm{Be}}^{+}$ ions that are trapped simultaneously in a Penning trap. The ultraviolet resonance lines (5 ${\mathit{s}}^{\mathrm{}2}$ ${\mathit{S}}_{1/2}$ \ensuremath{\leftrightarrows}5 ${\mathit{p}}^{\mathrm{}2}$ ${\mathit{P}}_{3/2}$ , \ensuremath{\lambda}=214.5 nm) of the cooled ${\mathrm{Cd}}^{+}$ ions were observed using a frequency-doubled cw dye laser. This radiation is based on efficient frequency doubling in a nonlinear crystal [\ensuremath{\beta}- ${\mathrm{BaB}}_{2}$ ${\mathrm{O}}_{4}$ (BBO)] with an external enhancement cavity. The spectra of the six isotopes (A=110--114, and 116) were obtained using a natural isotope mixture, and the reliability of the measured isotope shifts is discussed. \textcopyright{} 1996 The American Physical Society.Cadmium ions (${\mathrm{Cd}}^{+}$) have been cooled sympathetically below 1 K by means of Coulomb interactions with laser-cooled ${\mathrm{Be}}^{+}$ ions that are trapped simultaneously in a Penning trap. The ultraviolet resonance lines (5${\mathit{s}}^{\mathrm{}2}$${\mathit{S}}_{1/2}$\ensuremath{\leftrightarrows}5${\mathit{p}}^{\mathrm{}2}$${\mathit{P}}_{3/2}$, \ensuremath{\lambda}=214.5 nm) of the cooled ${\mathrm{Cd}}^{+}$ ions were observed using a frequency-doubled cw dye laser. This radiation is based on efficient frequency doubling in a nonlinear crystal [\ensuremath{\beta}-${\mathrm{BaB}}_{2}$${\mathrm{O}}_{4}$ (BBO)] with an external enhancement cavity. The spectra of the six isotopes (A=110--114, and 116) were obtained using a natural isotope mixture, and the reliability of the measured isotope shifts is discussed. \textcopyright{} 1996 The American Physical Society.

Physical Review AJan 1, 199630 citations

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We demonstrate laser cooling of single174Yb+ions stored in a rf trap. Single174Yb+ions were loaded using a natural isotope mixture as source. To locate a single ion at the center of the trap, and consequently, to minimize the micromotion caused by the rf driving field, we introduced two compensation electrodes and applied dc voltages to them and to one of the endcap electrodes. We estimated the temperature of a trapped single174Yb+ion to be 150 mK from the residual Doppler width of the spectra observed by a frequency sweep of the cooling laser. In the estimation, the saturation broadening in the spectra was substituted by measurement of the power dependence of the spectral width. To count the number of trapped174Yb+ions, we detected sudden drops in the fluorescence intensity (quantum jumps) of individual ions caused by pumping to and deexcitation of the2F7/2state. We found that deexcitation of the2F7/2state is possible by driving the2F7/2–1D[3/2]3/2transition at 760 nm and the2F7/2–3D[9/2]7/2transition at 828 nm, in addition to the former methods of driving the2F7/2–1D[5/2]5/2transition at 639 nm and the2F7/2–2D5/2transition at 3.43 µm.We demonstrate laser cooling of single174Yb+ions stored in a rf trap. Single174Yb+ions were loaded using a natural isotope mixture as source. To locate a single ion at the center of the trap, and consequently, to minimize the micromotion caused by the rf driving field, we introduced two compensation electrodes and applied dc voltages to them and to one of the endcap electrodes. We estimated the temperature of a trapped single174Yb+ion to be 150 mK from the residual Doppler width of the spectra observed by a frequency sweep of the cooling laser. In the estimation, the saturation broadening in the spectra was substituted by measurement of the power dependence of the spectral width. To count the number of trapped174Yb+ions, we detected sudden drops in the fluorescence intensity (quantum jumps) of individual ions caused by pumping to and deexcitation of the2F7/2state. We found that deexcitation of the2F7/2state is possible by driving the2F7/2–1D[3/2]3/2transition at 760 nm and the2F7/2–3D[9/2]7/2transition at 828 nm, in addition to the former methods of driving the2F7/2–1D[5/2]5/2transition at 639 nm and the2F7/2–2D5/2transition at 3.43 µm.

Japanese Journal of Applied PhysicsApr 1, 19999 citations

Spatial separation of ion clouds between sympathetically laser-cooled Cd + -ion isotopes in a Penning trap

Hidetsuka Imajo, Kazuhiro Hayasaka, R. Ohmukai +3 more

Natural ${\mathrm{Cd}}^{+}$ ions in a Penning trap are cooled sympathetically below 1 K by a Coulomb interaction with directly laser-cooled ${\mathrm{Be}}^{+}$ ions. Spatial separation of the ${\mathrm{Be}}^{+}$ and ${\mathrm{Cd}}^{+}$ ion clouds due to centrifugal force is observed directly. When the frequency of rotation of the ion clouds is accelerated, the separation between ${\mathrm{Cd}}^{+}$ -ion isotopes (A=110 and 116) can be clearly observed, though their mass difference is very small. The equations of motion for 100 ${\mathrm{Be}}^{+}$ ions and 50 ${\mathrm{Cd}}^{+}$ ions are solved to simulate the experiments, and the result shows the spatial separation between the two ion species. The separation between the ${\mathrm{Cd}}^{+}$ -ion isotopes is investigated by comparing the experimental results with numerical calculations.Natural ${\mathrm{Cd}}^{+}$ ions in a Penning trap are cooled sympathetically below 1 K by a Coulomb interaction with directly laser-cooled ${\mathrm{Be}}^{+}$ ions. Spatial separation of the ${\mathrm{Be}}^{+}$ and ${\mathrm{Cd}}^{+}$ ion clouds due to centrifugal force is observed directly. When the frequency of rotation of the ion clouds is accelerated, the separation between ${\mathrm{Cd}}^{+}$ -ion isotopes (A=110 and 116) can be clearly observed, though their mass difference is very small. The equations of motion for 100 ${\mathrm{Be}}^{+}$ ions and 50 ${\mathrm{Cd}}^{+}$ ions are solved to simulate the experiments, and the result shows the spatial separation between the two ion species. The separation between the ${\mathrm{Cd}}^{+}$ -ion isotopes is investigated by comparing the experimental results with numerical calculations.

Physical Review AFeb 1, 199725 citations

Zero-point cooling and low heating of trapped Cd+111 ions

Louis Deslauriers, P. C. Haljan, P. J. Lee +4 more

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arXiv:quant-ph/0404142Physical Review AOct 18, 2004112 citations

Laser cooling of a natural isotope mixture of Yb/sup +/ stored in an RF trap

K. Sugiyama, Jun Yoda

We demonstrate laser cooling of Yb/sup +/, produced by ionization of a natural isotope mixture, stored in an RF trap. One of the three major even isotopes was directly laser cooled and other isotopes were simultaneously trapped as a result of sympathetic cooling. It was possible to carry out laser cooling to the temperature at which the cloud-to-crystal phase transition occurs for /sup 174/Yb/sup +/, as observed in the case where enriched isotopes are used. We observed sudden drops of fluorescence owing to pumping to the /sup 2/F/sub 7/2/ state in the case of a small number of trapped Yb/sup +/ ions.>We demonstrate laser cooling of Yb/sup +/, produced by ionization of a natural isotope mixture, stored in an RF trap. One of the three major even isotopes was directly laser cooled and other isotopes were simultaneously trapped as a result of sympathetic cooling. It was possible to carry out laser cooling to the temperature at which the cloud-to-crystal phase transition occurs for /sup 174/Yb/sup +/, as observed in the case where enriched isotopes are used. We observed sudden drops of fluorescence owing to pumping to the /sup 2/F/sub 7/2/ state in the case of a small number of trapped Yb/sup +/ ions.>

IEEE Transactions on Instrumentation and MeasurementApr 1, 199510 citations

Cadmium ions (

{\mathrm{Cd}}^{+}

) have been cooled sympathetically below 1 K by means of Coulomb interactions with laser-cooled

{\mathrm{Be}}^{+}

ions that are trapped simultaneously in a Penning trap. The ultraviolet resonance lines (5

{\mathit{s}}^{\mathrm{}2}

{\mathit{S}}_{1/2}

\ensuremath{\leftrightarrows}5

{\mathit{p}}^{\mathrm{}2}

{\mathit{P}}_{3/2}

, \ensuremath{\lambda}=214.5 nm) of the cooled

{\mathrm{Cd}}^{+}

ions were observed using a frequency-doubled cw dye laser. This radiation is based on efficient frequency doubling in a nonlinear crystal [\ensuremath{\beta}-

{\mathrm{BaB}}_{2}

{\mathrm{O}}_{4}

(BBO)] with an external enhancement cavity. The spectra of the six isotopes (A=110--114, and 116) were obtained using a natural isotope mixture, and the reliability of the measured isotope shifts is discussed. \textcopyright{} 1996 The American Physical Society.

Natural

{\mathrm{Cd}}^{+}

ions in a Penning trap are cooled sympathetically below 1 K by a Coulomb interaction with directly laser-cooled

{\mathrm{Be}}^{+}

ions. Spatial separation of the

{\mathrm{Be}}^{+}

and

{\mathrm{Cd}}^{+}

ion clouds due to centrifugal force is observed directly. When the frequency of rotation of the ion clouds is accelerated, the separation between

{\mathrm{Cd}}^{+}

-ion isotopes (A=110 and 116) can be clearly observed, though their mass difference is very small. The equations of motion for 100

{\mathrm{Be}}^{+}

ions and 50

{\mathrm{Cd}}^{+}

ions are solved to simulate the experiments, and the result shows the spatial separation between the two ion species. The separation between the

{\mathrm{Cd}}^{+}

-ion isotopes is investigated by comparing the experimental results with numerical calculations.

We report on ground-state laser cooling of single

^{111}\mathrm{Cd}^{+}

ions confined in radio-frequency (Paul) traps. Heating rates of trapped ion motion are measured for two different trapping geometries and electrode materials, where no effort was made to shield the electrodes from the atomic

\mathrm{Cd}

source. The low measured heating rates suggest that trapped

^{111}\mathrm{Cd}^{+}

ions may be well suited for experiments involving quantum control of atomic motion, including applications in quantum information science.