Effect of buffer gases on Rydberg electromagnetically induced transparency in rubidium vapor cells

Rydberg electromagnetically induced transparency (EIT) can be used for SI-traceable DC and AC electromagnetic-field sensing. In this work, we demonstrate Rydberg-EIT in rubidium (Rb) vapor cells containing buffer gasses of several species at various pressures. We investigate how the presence of buffer gas affects the EIT signal. With a buffer-gas-free Rb vapor cell as reference, we measure frequency shift and line broadening of the EIT spectra in Rb vapor cells with argon, neon or nitrogen buffer gases at pressures ranging from a few mTorr to 5 Torr. The results qualitatively agree with a model that includes s-wave scattering between the Rydberg electron and the buffer-gas atoms, and the effect of polarization of the buffer-gas atoms by the Rydberg atoms. This study aims at establishing Rydberg-EIT as an all-optical and non-intrusive spectroscopic probe for field diagnostics in low-pressure RF discharges.