An optical atomic clock using 4DJ states of rubidium

We analyze an optical atomic clock using two-photon 5S(1/2)-> 4D(J) transitions in rubidium. Four one- and two-color excitation schemes to probe the fine-structure states 4D(3/2) and 4D(5/2) are considered in detail. We compare key characteristics of Rb 4D(J) and 5D(5/2) two-photon clocks. The 4DJ clock features a high signal-to-noise ratio due to two-photon decay at favorable wavelengths, low dc electric and magnetic susceptibilities, and minimal black-body shifts. Ac Stark shifts from the clock interrogation lasers are compensated by two-color Rabi-frequency matching. We identify a "magic" wavelength near 1060 nm, which allows for in-trap, Doppler-free clock-transition interrogation with lattice-trapped cold atoms. From our analysis of clock statistics and systematics, we project a quantum-noise-limited relative clock stability at the 10(-13)/root tau(s)-level, with integration time tau in seconds, and a relative accuracy of similar to 10(-13). We describe a potential architecture for implementing the proposed clock using a single telecom clock laser at 1550 nm, which is conducive to optical communication and long-distance clock comparisons. Our work could be of interest in efforts to realize small and portable Rb clocks and in high-precision measurements of atomic properties of Rb 4D(J)-states.