Abstract
We experimentally investigate an optical frequency standard based on the electric octupole () transition of a single trapped ion. For the spectroscopy of this strongly forbidden transition, we utilize a Ramsey-type excitation scheme that provides immunity to probe-induced frequency shifts. The cancellation of these shifts is controlled by interleaved single-pulse Rabi spectroscopy, which reduces the related relative frequency uncertainty to . To determine the frequency shift due to thermal radiation emitted by the ion’s environment, we measure the static scalar differential polarizability of the transition as and a dynamic correction . This reduces the uncertainty due to thermal radiation to . The residual motion of the ion yields the largest contribution () to the total systematic relative uncertainty of the clock of .
- Received 27 November 2015
DOI:https://doi.org/10.1103/PhysRevLett.116.063001
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