Design studies for a high-stability laser-cooled rubidium local oscillator

The combination of a low-velocity intense source (LVIS) for Rubidium (Rb) atoms, along with a Ramsey cavity presents interesting alternatives to either traditional beam-type clocks or to the fountain geometry. The basic idea is not new, and much of the original thinking for such a clock has been described previously by Buell and Jaduszliwer [1999]. The current study differs in significant detail from their device. First, the device we describe is much larger having been optimized for laboratory use as a local oscillator rather than use as a transportable standard. Also, the use of phase modulation allows local oscillator locking at much less than the Ramsey interrogation time. Magnetic deflection of the atoms reduces the complexity of the device while simultaneously diminishing instabilities associated with resonant light. A less significant difference is the use of Rb in place of Cs. The clock should produce stabilities of σ_y(τ)~10 ^-14 τ^-1/2