Abstract

Very weak fields stored in a high Q microwave cavity induce large energy shifts on Rydberg atomic levels. If a transition connecting two Rydberg states is sightly off- resonant with a cavity mode, these states are shifted in opposite directions. For large enough atom-cavity detuning, the resulting atomic transition frequency shift is proportional to $N+\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$, where N is the average photon number in the cavity. A residual vacuum effect, equivalent to the shift induced by "half a photon" is produced by an empty cavity.

© 1994 Optical Society of America