Optical clock/frequency standard at 657 nm based on laser-cooled neutral calcium atoms

Summary form only given. We have constructed an all-laser-diode optical frequency/time reference based on the /sup 1/S/sub 0/-/sup 3/P/sub 1/ transition in neutral Ca at 657 nm. Recent improvements have led to reduced short-term frequency fluctuations (<5 /spl times/ 10/sup -15/ (2 Hz) @ 1s) and enabled an absolute frequency measurement with less than 40 Hz uncertainty. Moreover, the revolution in optical clockwork due to the development of fs-laser-based frequency combs enables operation of this standard as an optical clock, with the potential to transfer the stability of the optical source to the microwave domain.