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Physical Review A

Ionic crystals in a linear Paul trap

Mark G. Raizen, Jonathan Magnolia Gilligan, Jonas Bergquist, W. M. Itano, D. J. Wineland

Published May 1, 1992• 330 citations
Publisher

Abstract

We describe a configuration for a linear Paul rf ion trap. This trap can store a long string of ions with a small second-order Doppler shift, comparable to that achieved with a single ion in a quadrupole Paul trap. Crystallized strings of trapped ions, as well as more complicated structures, have been observed in the trap. We report an observation of the 40.5-GHz ground-state hyperfine interval of $^{199}\mathrm{Hg}^{+}$ by microwave-optical double-resonance spectroscopy and discuss prospects for a microwave frequency standard based on a trapped string of ions.

DOI
10.1103/physreva.45.6493

Related papers

Linear Trap for High-accuracy Spectroscopy of Stored Ions

Mark G. Raizen, Jonathan Magnolia Gilligan, Jonas Bergquist +2 more

In a linear r.f. Paul trap, ‘crystallized’ structures of laser-cooled 199Hg+ ions are observed. The ground-state hyperfine transition at 40·5 GHz is observed in microwave-optical double-resonance spectroscopy. Future prospects are also discussed.

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Beads on a string: experiments with a linear rf ion trap

Mark G. Raizen, Jonas Bergquist, Jonathan Magnolia Gilligan +2 more

Trapping and cooling large numbers of ions, each confined to much less than an optical wavelength, is of great interest for high accuracy spectroscopy, improved frequency standards and atom-radiation field experiments. This can be achieved in a linear rf ion trap where the rf electric fields go to zero along a line rather than at only a point. As a step toward this goal we have constructed a linear trap and have observed simple crystallized linear structures of up to tens of 199Hg+ ions. By varying the axial well depth (determined by a static potential) we have also observed more complex crystallized structures. The ion positions in these structures are in close agreement with a calculation that used as input the measured secular frequencies of the trap. We have also observed the 40.5-GHz ground-state hyperfine transition of trapped 199Hg+ ions by microwave/optical double resonance.

Annual Meeting Optical Society of America•Jan 1, 1991•0 citations

Laser-microwave double resonance frequency standard using {sup 199}Hg{sup +} ions in a cryogenic linear trap

Martin E. Poitzsch, Jonas Bergquist, W. M. Itano +1 more

We have previously reported experiments using a linear rf trap to store laser-cooled {sup 199}Hg{sup +} ions. Trapping multiple ions increases the signal-to-noise ratio; yet all ions have equally low second-order Doppler shifts if they are confined along the nodal center line of a linear trap. In such an environment, the 40.5 GHz ground-state hyperfine transition in {sup 199}Hg{sup +} is a candidate for an extremely accurate and stable microwave frequency standard. Our redesigned apparatus will operate at cryogenic temperatures to provide very low background gas pressure (resulting in longer ion storage times and immunity from background pressure shifts) and superconductive shielding against stray magnetic fields. We shall discuss progress on this frequency standard and applications of our apparatus to new cooling and squeezing techniques.

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Quantum Electronics•May 9, 2017•4 citations

Progress at CSIRO Australia towards a microwave frequency standard based on trapped, laser-cooled /sup 171/Yb/sup +/ ions

Peter Fisk, M.A. Lawn, C. Coles

The authors report preliminary results of precision microwave-optical double resonance spectroscopy on buffer gas cooled /sup 171/Yb/sup +/ ions confined in a linear Paul trap as a microwave frequency standard at 12.6 GHz. They also report laser cooling of trapped /sup 171/Yb/sup +/ ions. Temperatures below 1 K have been achieved, and evidence for a phase transition to a crystal-like state has been found. This temperature is sufficiently low to reduce the fractional second-order Doppler shift of the microwave resonance to below 10/sup -14/.>

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Dec 30, 2002•1 citation

Rf-induced persistent long-range ordered structures in two-species ion Coulomb crystals in a linear Paul trap

A. Mortensen, Nielsen, E., Thierry Matthey +1 more

We report on the observations of three-dimensional long-range ordered structures in the central $^{40}$Ca$^+$ ion component of $^{40}$Ca$^+$--$^{44}$Ca$^+$ two-species ion Coulomb crystals in a linear Paul trap. In contrast to long-range ordering previously observed in single species crystals, the structures observed are strikingly persistent and always of one specific type in one particular orientation. Molecular dynamics simulations strongly indicate that these characteristics are a hitherto unpredicted consequence of the co-axial cylindrical symmetry of the central ion component of the Coulomb crystal and the radio frequency quadrupole trapping field.

arXiv:physics/0608062•Aug 7, 2006•0 citations
We describe a configuration for a linear Paul rf ion trap. This trap can store a long string of ions with a small second-order Doppler shift, comparable to that achieved with a single ion in a quadrupole Paul trap. Crystallized strings of trapped ions, as well as more complicated structures, have been observed in the trap. We report an observation of the 40.5-GHz ground-state hyperfine interval of 199Hg+^{199}\mathrm{Hg}^{+}199Hg+ by microwave-optical double-resonance spectroscopy and discuss prospects for a microwave frequency standard based on a trapped string of ions.
Trapping and cooling large numbers of ions, each confined to much less than an optical wavelength, is of great interest for high accuracy spectroscopy, improved frequency standards and atom-radiation field experiments. This can be achieved in a linear rf ion trap where the rf electric fields go to zero along a line rather than at only a point. As a step toward this goal we have constructed a linear trap and have observed simple crystallized linear structures of up to tens of 199Hg+ ions. By varying the axial well depth (determined by a static potential) we have also observed more complex crystallized structures. The ion positions in these structures are in close agreement with a calculation that used as input the measured secular frequencies of the trap. We have also observed the 40.5-GHz ground-state hyperfine transition of trapped 199Hg+ ions by microwave/optical double resonance.
We have previously reported experiments using a linear rf trap to store laser-cooled {sup 199}Hg{sup +} ions. Trapping multiple ions increases the signal-to-noise ratio; yet all ions have equally low second-order Doppler shifts if they are confined along the nodal center line of a linear trap. In such an environment, the 40.5 GHz ground-state hyperfine transition in {sup 199}Hg{sup +} is a candidate for an extremely accurate and stable microwave frequency standard. Our redesigned apparatus will operate at cryogenic temperatures to provide very low background gas pressure (resulting in longer ion storage times and immunity from background pressure shifts) and superconductive shielding against stray magnetic fields. We shall discuss progress on this frequency standard and applications of our apparatus to new cooling and squeezing techniques.
The authors report preliminary results of precision microwave-optical double resonance spectroscopy on buffer gas cooled /sup 171/Yb/sup +/ ions confined in a linear Paul trap as a microwave frequency standard at 12.6 GHz. They also report laser cooling of trapped /sup 171/Yb/sup +/ ions. Temperatures below 1 K have been achieved, and evidence for a phase transition to a crystal-like state has been found. This temperature is sufficiently low to reduce the fractional second-order Doppler shift of the microwave resonance to below 10/sup -14/.>
We report on the observations of three-dimensional long-range ordered structures in the central 40^{40}40Ca+^++ ion component of 40^{40}40Ca+^++--44^{44}44Ca+^++ two-species ion Coulomb crystals in a linear Paul trap. In contrast to long-range ordering previously observed in single species crystals, the structures observed are strikingly persistent and always of one specific type in one particular orientation. Molecular dynamics simulations strongly indicate that these characteristics are a hitherto unpredicted consequence of the co-axial cylindrical symmetry of the central ion component of the Coulomb crystal and the radio frequency quadrupole trapping field.