Motivation
Quantum metrology demonstrates that atomic references for precision measurements have exceptional sensitivity and self-calibrating behavior. Microwave sensing in particular is reliant on antenna calibration and requires sophisticated signal processing to attempt to distinguish between incoherent thermal radiation and coherent fields. Prior to this work, state-of-the-art microwave sensitivity measurements using atomic vapors relied on experimental techniques to reduce the laser linewidth, as the optical linewidths dominate the atomic linewidths by many orders of magnitude. This work applied techniques from NMR to decouple the sensitivity from the optics: which is enabled by the long lifetime of the Rydberg state.
Summary
This publication presents work on Rydberg atom dark evolution sensing (RADES), demonstrating the achievement of 10nV/cm/√Hz sensitivity at 10GHz. The experimental technique used a Cesium vapor cell with a 2-photon counter-propagating electromagnetically induced transparency (EIT) set up to create the Rydberg population, which could then be driven coherently with a microwabe signal detuned from the sensing frequency of interest. With the driven microwave energy levels acting as a spin-1/2 system, the driving microwave field is applied as a pi/2 pulse. The detuning between the driving field and the frequency of interest generates a phase that tips the state vector on a Bloch sphere model of the system.
Key Contributions
- Demonstrated Rydberg atom dark evolution sensing (RADES) achieving unprecedented electric field sensitivity
- Decoupled sensitivity gains from laser linewidths by exploiting coherence time of cesium rydberg states
- Technique applies to thermal atomic vapors
- Demonstrated 3 microsecond long Rabi precession in the microwave field
Related Research
This publication is based on research conducted in the Rydberg Atom Dark Evolution Sensing (RADES) project.