Detecting electric fields using Rydberg electrometry in low temperature plasmas

We introduce a novel diagnostic method to non-invasively measure electric fields in low temperature plasmas using all-optical quantum sensing techniques. Our approach relies on Rydberg Electromagnetically Induced Transparency (Ry-EIT), in which a narrow two-photon optical resonance creates a narrow optical transparency window that allows to accurately measure electric field-induced energy shifts of Rb Rydberg states. We use such Rb vapor as a local E-field sensor in a low-pressure Ar plasma. Using optical transmission measurements, we observe, strong electric field screening and significant Ry-EIT resonance broadening by the plasma. We also create 2D maps of inhomogeneous e-field with sub-mm spatial resolution and sensitivity in the V/cm range, using fluorescence imaging. Ongoing work aims to enhance sensitivity and enable vector field reconstruction. This technique is a powerful tool for advanced plasma diagnostics, particularly in the sheath and pre-sheath regions.