Non-perturbative 2D spatial measurements of electric fields within a plasma sheath

TL;DR

This paper presents a novel all-optical, quantum-enhanced method for non-invasively measuring 2D electric field profiles within low-temperature plasmas, achieving high sensitivity and spatial resolution.

Contribution

It introduces a new quantum optical technique using Rydberg electromagnetically induced transparency for detailed electric field mapping in plasma sheaths.

Findings

Achieved electric field sensitivity exceeding 1 V/cm.

Reconstructed 2D electric field profiles with 30 μm resolution.

Demonstrated measurement of electric field changes around a biased probe.

Abstract

We introduce an all-optical quantum-enhanced diagnostic for electric fields in low-temperature plasmas. Trace amounts of rubidium vapor, added to argon plasma, allow us to produce spectrally narrow electric field-sensitive optical resonances via quantum optical effect of Rydberg electromagnetically induced transparency, and to non-invasively measure electric field in plasma with sensitivity exceeding 1 V/cm. By collecting fluorescence from the illuminated region of interest, we reconstruct a 2D spatial profile of the electric field magnitude with $30~\mu$m resolution. As a proof-of-principle demonstration, we measured the changes in electric field within the plasma sheath surrounding a biased Langmuir probe tip. This method holds significant potential for studying sheath structures in low-temperature plasmas.