High-Sensitivity Rydberg Electrometry with Extended Dynamic Range and Frequency Response

Highly excited Rydberg atoms possess large dipole moments, offering significant potential for sensing weak electric fields. In this work, we introduce a heterodyne detection system based on Rydberg electromagnetically induced transparency (EIT) spectroscopy, utilizing two microwave (MW) tones as AC electric field sources. The MW frequency band (13 to 16 GHz) is selected to drive transitions between Rb Rydberg states ( |53D> to |54P> or |53D> to |52F>), allowing them to serve as effective reference fields. Our results demonstrate that this scheme can measure field strengths down to a few μV/cm, with a detectable dynamic power range of up to 60 dB. By combining these results with the Autler-Townes splitting regime, the total dynamic range is extended to 90 dB. The two closed transitions, separated by approximately 1.3 GHz, preserve the response signal power while extending the detectable frequency band to around 3 GHz, maintaining a signal power more than 10 dB above the heterodyne system's noise floor. We further determined the optimal field strength for maximizing the signal response and confirmed the field strength dependencies of the resonant Autler-Townes regime and the detuned AC Stark regime. These results highlight the potential for further enhancing the detectable bandwidth or minimum detectable field power by utilizing other Rydberg states, thereby advancing the development of precise Rydberg-based atomic sensors.