We demonstrate a movable, Rydberg atom-based radio frequency (RF) electric (E) field probe. The technique is based on electromagnetically induced transparency and Autler-Townes splitting. Two fibers attached to a 10 mm cubic Cs133 vapor cell are used to couple counter-propagating probe and control lasers through the cell. This all-dielectric fiber-coupled sensor can be moved from the optics table to locations more suitable for RF (gigahertz to sub-terahertz) E-field measurements and calibrations.
An experimental study on Rydberg electromagnetically induced transparency (EIT) in rubidium (Rb) vapor cells containing inert gases at pressures ≤5 Torr is reported. Using an inert-gas-free Rb vapor cell as a reference, we measure frequency shift and line broadening of the EIT spectra in Rb vapor cells with argon, neon, or nitrogen gases at pressures ranging from a few mTorr to 5 Torr. The results qualitatively agree with a pseudo-potential model that includes s-wave scattering between the Rydberg electron and the inert-gas atoms and the effect of polarization of the inert-gas atoms by the Rydberg atoms. Our results are important for establishing Rydberg-EIT as an all-optical and non-intrusive spectroscopic probe for field diagnostics in low-pressure radio frequency discharges.
We report on rubidium vapor-cell Rydberg electromagnetically induced transparency (EIT) in a 0.7~T magnetic field where all involved levels are in the hyperfine Paschen-Back regime, and the Rydberg state exhibits a strong diamagnetic interaction with the magnetic field. Signals from both
85Rb and
87Rb are present in the EIT spectra. This feature of isotope-mixed Rb cells allows us to measure the field strength to within a
±0.12\% relative uncertainty. The measured spectra are in excellent agreement with the results of a Monte Carlo calculation and indicate unexpectedly large Rydberg-level dephasing rates. Line shifts and broadenings due to small inhomogeneities of the magnetic field are included in the model.