Description
We intend to build a vapor cell atomic optical clock which uses optical transition (instead of microwave transition) in Rb-87 atoms, as shown in the diagrams on the right. And we aim to achieve a fractional frequency uncertainty <6×10⁻¹4 @1s integration time. Further we intend to miniaturize this to chip-scale.
Here frequency combs are used to divide the very high optical frequency (385.284 THz) down to the microwave domain (22 GHz) so that we can use rf electronics. This process is called optical frequency division, and it maintains the stability of the optical reference while outputting a more usable microwave clock signal. Experimentally, this consists of a semiconductor laser local oscillator locked to the Rb-87 two-photon transition at 385.284 THz that is coherently divided down to a 22 GHz clock tone by stabilizing a pair of interlocked microresonator frequency combs (microcombs) to the local oscillator, as shown in the diagrams on the right.
