2023/04/18 by Hao, Jianhai, Jia, Fengdong, Cui, Yue +6
#Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2304.09316
We have theoretically and experimentally studied the dispersive signal of the Rydberg atomic electromagnetically induced transparency (EIT) - Autler-Townes (AT) splitting spectra obtained using amplitude modulation of the microwave (MW) field. In addition to the two zero-crossing points, the dispersion signal has two positive maxima with an interval defined as the shoulder interval of the dispersion signal Δfsho. The relationship of MW field strength EMW and Δfsho are studied at the MW frequencies of 31.6 GHz, 22.1 GHz, and 9.2 GHz respectively. The results show that Δfsho can be used to character the much weaker EMW than the interval of two zero-crossing points Δfzeros and the traditional EIT-AT splitting interval Δfm, the minimum EMW measured by Δfsho is about 30 times smaller than that by Δfm. As an example, the minimum EMW at 9.2 GHz that can be characterized by Δfsho is 0.056 mV/cm, which is the minimum value characterized by frequency interval using vapour cell without adding any auxiliary fields. The proposed method can improve the weak limit and sensitivity of EMW measured by spectral frequency interval, which is important in the direct measurement of weak EMW.