Absolute frequency measurement of the ? optical clock transition in ? with an uncertainty of ? using a frequency link to international atomic time
Abstract
The highly forbidden ? electric octupole transition in ? is a potential candidate for a redefinition of the SI second. We present a measurement of the absolute frequency of this optical transition, performed using a frequency link to International Atomic Time to provide traceability to the SI second. The ? optical frequency standard was operated for 76% of a 25-day period, with the absolute frequency measured to be 642 121 496 772 645.14(26) Hz. The fractional uncertainty of ? is comparable to that of the best previously reported measurement, which was made by a direct comparison to local caesium primary frequency standards.
- Publication:
-
Journal of Modern Optics
- Pub Date:
- March 2018
- DOI:
- 10.1080/09500340.2017.1384514
- arXiv:
- arXiv:1707.00646
- Bibcode:
- 2018JMOp...65..585B
- Keywords:
-
- Frequency metrology;
- optical frequency standards;
- international atomic time;
- Physics - Atomic Physics
- E-Print:
- 10 pages, 3 figures. Corrected typos - no changes to any numbers or results from version1