Plasma field diagnostics based on Rydberg Electromagnetically Induced Transparency

We present a novel, all-optical, and non-invasive plasma field diagnostic technique, based on Rydberg Electromagnetically Induced Transparency (EIT). Rydberg atoms, owing to their extremely high polarizability, exhibit large Stark shifts in response to electric fields. These shifts can be detected with high precision using narrow-linewidth lasers via EIT, a coherent quantum optical phenomenon. We demonstrate in-situ electric field measurements in a continuous inductively coupled RF Argon plasma at pressures of a few millitorr, using Rydberg-EIT spectroscopy of Rubidium vapor seeded into the discharge. From the measured spectra, we extract the Holtsmark field distribution and observe screening of the applied RF field within the discharge volume. We also report on progress toward spatiotemporally resolved field mapping, with potential implications for diagnostics in dusty plasma.