The optical calcium frequency standards of PTB and NIST

Abstract

We describe the current status of the Ca optical frequency standards with laser-cooled neutral atoms realized in two different laboratories for the purpose of developing a possible future optical atomic clock. Frequency measurements performed at the Physikalisch-Technische Bundesanstalt (PTB) and the National Institute of Standards and Technology (NIST) make the frequency of the clock transition of 40Ca one of the best known optical frequencies (relative uncertainty 1.2e-14) and the measurements of this frequency in both laboratories agree to well within their respective uncertainties. Prospects for improvement by orders of magnitude in the relative uncertainty of the standard look feasible.

arXiv comment13 pages, 11 figures, to appear in Comptes Rendus Physique

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• Sub-dekahertz ultraviolet spectroscopy of 199Hg+
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• Spectroscopy of the ${}^1{S}_0-{}^3{P}_0$ Clock Transition of ${}^{87}$Sr in an Optical Lattice
• An Optical Clock with Ultracold Neutral Atoms
• Absolute frequency measurement of the 171Yb+ clock transition with a Kerr-lens mode-locked femtosecond laser
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Cited by in corpus (19)

• Atom Interferometers
• Direct excitation of the forbidden clock transition in neutral 174Yb atoms confined to an optical lattice
• Magnetic field-induced spectroscopy of forbidden optical transitions with application to lattice-based optical atomic clocks
• Systematic study of the ${}^{87}$Sr clock transition in an optical lattice
• Optical atomic coherence at the one-second time scale
• Long-distance frequency dissemination with a resolution of 10-17
• The absolute frequency of the 87Sr optical clock transition
• Bose-Einstein condensation of alkaline earth atoms: ${}^{40}${Ca}
• Atom interferometry with the Sr optical clock transition
• An accurate optical lattice clock with 87Sr atoms
• Hyperpolarizability effects in a Sr optical lattice clock
• From Optical Lattice Clocks to the Measurement of Forces in the Casimir Regime
• Sideband cooling while preserving coherences in the nuclear spin state in group-II-like atoms
• Dynamic cancellation of ac Stark shift for pulsed EIT/Raman optical lattice clocks
• Bose-Einstein condensation of 86Sr
• Improved magneto-optical trapping of Ca
• Testing ultrafast mode-locking at microhertz relative optical linewidth
• Violation of the equivalence principle induced by oscillating rest mass and transition frequency, and its detection in atom interferometers
• Laser-cooling Cadmium Bosons and Fermions with Near Ultraviolet Triplet Excitations