171Yb+ single-ion optical frequency standard at 688 THz

Two <sup>171</sup>Yb<sup>+</sup> single-ion optical frequency standards operating at 688 THz (436 nm) are compared in order to investigate systematic frequency shifts in the sub-Hertz range. In the absence of externally applied perturbations, a mean relative frequency difference of 3.8(6.1)·10<sup>-16</sup> is observed. This agreement is comparable to that of the most accurate comparisons between cesium fountain clocks. Using a femtosecond frequency comb generator based on a Er<sup>3+</sup>-doped fiber laser, the frequency of the <sup>171</sup>Yb<sup>+</sup> standard is measured with a relative systematic uncertainty of 3.1·10<sup>-15</sup> and a statistical uncertainty of 0.6·10<sup>-15</sup>.

[1]  Wayne M. Itano,et al.  External-Field Shifts of the 199Hg+ Optical Frequency Standard , 2000, Journal of research of the National Institute of Standards and Technology.

[3]  H R Telle,et al.  Absolute frequency measurement of the 435.5-nm (171)Yb+-clock transition with a Kerr-lens mode-locked femtosecond laser. , 2001, Optics letters.

[4]  Gesine Grosche,et al.  Phase-locked two-branch erbium-doped fiber laser system for long-term precision measurements of optical frequencies. , 2004, Optics express.

[5]  Ekkehard Peik,et al.  Laser frequency stabilization to a single ion , 2005, physics/0511168.

[6]  D. Engelke,et al.  Spectroscopy of the electric-quadrupole transition 2 S 1/2 (F=0)- 2 D 3/2 (F=2) in trapped 171 Yb + , 2000 .

[7]  P. Gill,et al.  On secondary representations of the second , 2006, Proceedings of the 20th European Frequency and Time Forum.

[8]  W. Itano.  Quadrupole moments and hyperfine constants of metastable states of Ca{sup +}, Sr{sup +}, Ba{sup +}, Yb{sup +}, Hg{sup +}, and Au , 2005, physics/0512250.

[9]  B Lipphardt,et al.  Limit on the present temporal variation of the fine structure constant. , 2004, Physical review letters.

[10]  W. Itano,et al.  Measurement of the (199)Hg+ 5d9 6s2 (2)D(5/2) electric quadrupole moment and a constraint on the quadrupole shift. , 2005, Physical review letters.

[11]  T Schneider,et al.  Sub-Hertz optical frequency comparisons between two trapped 171Yb+ ions. , 2005, Physical review letters.

[12]  Michael E. Tobar,et al.  Advances in atomic fountains , 2004 .

[13]  J. Bernard,et al.  Electric quadrupole shift cancellation in single-ion optical frequency standards. , 2005, Physical review letters.

[14]  Patrick Gill,et al.  Trapped Ion Optical Frequency Standards , 2003 .