Stabilization of a laser to an optical-clock transition has been demonstrated using Ramsey's phase-modulation technique. The technique was implemented using a 674 nm laser and a component of the 5 s S-2(1/2) -> 4d D-2(5/2) optical clock transition in a single Sr-88(+) ion. The lock performance observed was consistent with the short-term stability of the local oscillator. Compared with existing frequency-modulation stabilization schemes, this technique offers advantages for use in single-ion optical clocks through its possible increased resolution and the ability to conveniently compensate known systematic shifts. (c) 2006 Optical Society of America.
- frequency standards
- femtosecond laser