Optical Frequency Standard Based on an Electric Octupole Transition in 171Yb

The frequency of the 2 S 1/2 (F = 0) - 2 F 7/2 (F = 3, m F = 0) transition in a single, trapped, laser cooled ion of 171 Yb + has been measured with a femtosecond laser frequency comb generator. The uncertainty is limited by measurement statistics and by the AC Stark shift