Rydberg-atom-based measurements of microwave electric fields with cavity quantum electrodynamics

Abstract

A scheme for enhancing the measurement of microwave electric (MW E) fields based on a cavity-quantum-electrodynamics (CQED) system consisting of an optical resonator coupled with four-level cold Rydberg atoms is analyzed in the paper. The strong collective coupling of the CQED cavity compresses the linewidth of the electromagnetically induced transparency signal substantially, which can be used to enhance the measurement. Our simulation results show that the minimum detectable strength of MW E-field can be enhanced by 196.7 and 26.2 times smaller than the separate atomic medium scheme and the weak coupling scheme, respectively. The detectable minimum strength in the present work can reach as low as 396.5nVcm−1. In addition, compared with the other two schemes, our work can increase the spectrum resolution respectively by about 216 and 10 times. The proposed scheme shows a broadband tunability and can be used in a broad detection range.