Using amplitude modulation of the microwave field to improve the sensitivity of Rydberg-atom based microwave electrometry

The microwave (MW) field can be measured by the Autler–Townes (AT) splitting of electromagnetically induced transparency (EIT) spectrum in Rydberg atomic system; however, EIT-AT method fails weak MW fields. We used amplitude modulation to resolve interval directly obtained, and minimum detectable strength is improved six times compared with traditional method. proposed more intuitive convenient for measuring fields practical applications.