Atomic stabilization of field intensity using Rabi resonances

Just as it is possible to stabilize the frequency of an electromagnetic field to an atomic resonance between energy eigenstates, it is possible to stabilize the intensity or brightness of a field to an atomic Rabi resonance. For ease of reference, such a stabilized field is termed an "atomic candle." Here, we describe a microwave atomic candle based on the (F = 2, m(F) = 0)-(F = 1, m(F) = 0) ground-state hyperfine transition of Rb-87 (6834.7 MHz) as observed in an optically pumped vapor. We discuss the atomic candle's operation and the intensity stability, of the field it produces (relative to the Rabi-resonance peak). We then discuss our use of the candle to investigate Rabi-resonance shifts. Specifically, we find that the Rabi resonance depends on the sc Stark shift of the hyperfine transition, the microwave field-atom detuning, and the alkali-metal vapor temperature.