Analysis of EIT Effect Under Different Fine Level Selections of Cesium D2-Line

In recent years, Rydberg atoms have been widely employed for electric field quantum measurements. The fundamental principle behind these measurements is the utilization of the double-photon three-level structure to achieve Electromagnetically Induced Transparency (EIT). When cesium atoms are employed as the sensor, the detection light needs to be locked at 852 nm to excite the cesium atoms from the ground state 6S1/2 to the intermediate state 6P3/2. Frequency locking is achieved through the saturated absorption spectroscopy method. Due to the fine energy level structure of the cesium atom's D2 line, the saturated absorption spectrum exhibits six spectral peaks, providing the flexibility to select any one of them as a reference for frequency locking. In this paper, we present an experimental setup where we compare the EIT effects resulting from frequency locking to five different spectral peaks and discuss the influencing factors and optimal selection.