Absolute frequency measurement of the 171Yb+ clock transition with a Kerr-lens mode-locked femtosecond laser

Abstract

We have measured the frequency of the $6s^2{S}_{1/2}-5d^2{D}_{3/2}$ electric-quadrupole transition of ${}^{171}$Yb${}^{+}$ with a relative uncertainty of $1\times 10^{-14}$, ${\nu }_{Yb}$ = 688 358 979 309 312 Hz $\pm$ 6 Hz. A femtosecond frequency comb generator was used to phase-coherently link the optical frequency derived from a single trapped ion to a cesium fountain controlled hydrogen maser. This measurement is one of the most accurate measurements of optical frequencies ever reported, and it represents a contribution to the development of optical clocks based on an ${}^{171}$Yb${}^{+}$ ion standard.

4 pages, 2 figures