Enhanced microwave electrometry with intracavity anomalous dispersion in Rydberg atoms

Intracavity anomalous dispersion is investigated and proposed to enhance detection sensitivity of weak microwave electric field with Rydberg atoms. When the Rydberg atoms are prepared with Raman gain and the cavity field serves as the probe field driving the metastable-state transition, two cavity modes are amplified due to the gain effect and two gain peaks appear in the cavity transmission, meanwhile, a large anomalous dispersion arises in the gain window. The frequency splitting of two gain peaks shows linear relationship with the MW field strength, which can be used to probe the MW electric-field strength. It is interesting to find that the anomalous dispersion broadens the frequency splitting of two gain peaks dramatically, so the probe sensitivity of MW field could be enhanced by 10 times from simulation, compared with the cavity-less scheme.