RF E-field Sensing Using Rydberg Atom-Based Microwave Electrometry

Abstract

In this work, a microwave field is sensed by rubidium atoms instead of a conventional antenna like dipole or horn antenna. Microwave field is projected onto a glass cell containing Rb vapors which act as an antenna in this case. A four-level ladder atomic system is considered for analytical solution, and E-field measurement is reported by utilizing quantum phenomena like electromagnetically induced transparency and Autler–Townes splitting. It has been shown that atoms can also sense weak microwave field with this approach. The amplitude measurement of microwave E-field is changed to frequency measurement, and E-field is evaluated by monitoring the frequency difference between two EIT peaks. Measurement results are reported for variable input microwave power at frequency 15.09 GHz varying from 12.5 μW to 4 mW generated from synthesized signal generator. Moreover, the effect on the EIT resonance due to the distance variation of the source antenna is also discussed. The microwave frequency is detuned from the resonant frequency, and results are reported in this work.