Radium Ion Optical Clock
Abstract
We report the first operation of a Ra+ optical clock, a promising high-performance clock candidate. The clock uses a single trapped 226Ra+ ion and operates on the 7 s 2S1/2 →6 d 2D5/2 electric quadrupole transition. By self-referencing three pairs of symmetric Zeeman transitions, we demonstrate a frequency instability of 1.1 ×10-13/√{τ } , where τ is the averaging time in seconds. The total systematic uncertainty is evaluated to be Δ ν /ν =9 ×10-16. Using the clock, we realize the first measurement of the ratio of the D5 /2 state to the S1 /2 state Landé g -factors: gD/gS=0.598 805 3 (11 ) . A Ra+ optical clock could improve limits on the time variation of the fine structure constant, α ˙/α , in an optical frequency comparison. The ion also has several features that make it a suitable system for a transportable optical clock.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2022
- DOI:
- 10.1103/PhysRevLett.128.033202
- arXiv:
- arXiv:2201.07330
- Bibcode:
- 2022PhRvL.128c3202H
- Keywords:
-
- Physics - Atomic Physics
- E-Print:
- Main text 5 pages, 3 figures. Supplemental material 5 pages, 1 figure