Abstract
For the past 50 years, atomic standards based on the frequency of the cesium ground-state hyperfine transition have been the most accurate time pieces in the world. We now report a comparison between the cesium fountain standard NIST-F1, which has been evaluated with an inaccuracy of about 4×10-16, and an optical frequency standard based on an ultraviolet transition in a single, laser-cooled mercury ion for which the fractional systematic frequency uncertainty was below 7.2×10-17. The absolute frequency of the transition was measured versus cesium to be 1064721609899144. 94 (97) Hz, with a statistically limited total fractional uncertainty of 9.1×10-16, the most accurate absolute measurement of an optical frequency to date.
Original language | English |
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Article number | 020801 |
Journal | Physical review letters |
Volume | 97 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2006 |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)