We investigate a technique for detecting radio frequency (RF) electric fields in a cesium (Cs) vapor cell at room temperature by collecting charges from ionized Rydberg atoms and compare its performance with the established method of electromagnetically induced transparency (EIT). By applying a known RF field, we measure the response from both the electrical (ionization current-based) and optical (EIT-based) readouts. The ionization current-based method yields a sensitivity of 22 μ V m−1 Hz−1/2, while the EIT-based method achieves 3.7 μ V m−1 Hz−1/2. The sensitivity of the ionization current-based method is limited by the 2.2 k Ω resistance between the collection electrodes, attributed to a thin Cs film on the inner surfaces of the vapor cell. Controlling or eliminating the Cs layer can significantly improve the sensitivity of this ionization approach.
Shylla et al. (Tue,) studied this question.