The “atomic candle:” progress towards a smart rubidium atomic clock [and application to microwave dielectric measurements]

Just as it is possible to stabilize the frequency of an electromagnetic field to an atomic resonance between energy eigenstates, so it is possible to stabilize the intensity or brightness of a field to an atomic Rabi-resonance. We term such a device an “atomic candle.” We describe the operation of a microwave atomic candle based on the 0-0 ground state hyperfine transition in ⁸⁷Rb, and our experiments examining its stability and sensitivity to various experimental parameters. Specifically, we have measured the microwave power stability of our candle, relative to the peak of the Rabi-resonance, and obtained σ_ΔPP/(τ)=9×10^-7+10^-7 √τ. Additionally, we examined the Rabi-resonance shift as a function of various experimental parameters including microwave detuning from the 0-0 resonance and resonance-cell temperature. The paper concludes with a discussion of a novel application of the atomic candle: the precision measurement of a material´s complex dielectric constant