Measurements of plasma electric fields are essential to the advancement of plasma science and applications. Performing non-invasive in situ measurements of plasma fields on sub-millimeter length scales with high sensitivity over a large range of field magnitude remains an outstanding challenge. We introduce and demonstrate a method for plasma electric field measurement that employs electromagnetically induced transparency as a high-resolution quantum-optical probe for the Stark energy level shifts of Rydberg atoms embedded in a plasma and serving as highly sensitive field sensors. The method is applied in diagnostics of plasmas generated by photo-excitation of a cesium vapor. The plasma electric fields are extracted from spatially resolved measurements of field-induced lineshape changes and shifts of Rydberg resonances in rubidium tracer atoms. Measurement capabilities over a range of plasma densities and temperatures are exploited to characterize plasmas in applied magnetic fields and to image electric-field distributions in cyclotron-heated plasmas. Our results pave the way toward further applications of Rydberg-atom-based field sensors to diagnostics and monitoring of electric fields due to plasmas.
Measurements of plasma electric fields are essential to the advancement of plasma science and applications. Performing non-invasive in situ measurements of plasma fields on sub-millimeter length scales with high sensitivity over a large range of field magnitude remains an outstanding challenge. We introduce and demonstrate a method for plasma electric field measurement that employs electromagnetically induced transparency as a high-resolution quantum-optical probe for the Stark energy level shifts of Rydberg atoms embedded in a plasma and serving as highly sensitive field sensors. The method is applied in diagnostics of plasmas generated by photo-excitation of a cesium vapor. The plasma electric fields are extracted from spatially resolved measurements of field-induced lineshape changes and shifts of Rydberg resonances in rubidium tracer atoms. Measurement capabilities over a range of plasma densities and temperatures are exploited to characterize plasmas in applied magnetic fields and to image electric-field distributions in cyclotron-heated plasmas. Our results pave the way toward further applications of Rydberg-atom-based field sensors to diagnostics and monitoring of electric fields due to plasmas.
Measurements of plasma electric fields are essential to the advancement of plasma science and applications. Methods for non-invasive in situ measurements of plasma fields on sub-millimeter length scales with high sensitivity over a large field range remain an outstanding challenge. Here, we introduce and demonstrate a new method for plasma electric field measurement that employs electromagnetically induced transparency as a high-resolution quantum-optical probe for the Stark energy level shifts of plasma-embedded Rydberg atoms, which serve as highly-sensitive field sensors with a large dynamic range. The method is applied in diagnostics of plasmas photo-excited out of a cesium vapor. The plasma electric fields are extracted from spatially-resolved measurements of field-induced shape changes and shifts of Rydberg resonances in rubidium tracer atoms. Measurement capabilities over a range of plasma densities and temperatures are exploited to characterize plasmas in applied magnetic fields and to image electric-field distributions in cyclotron-heated plasmas.
We present a non-invasive spectroscopic technique to measure electric fields in plasma, leveraging large polarizabilities and Stark shifts of Rydberg atoms. Rydberg Stark shifts are measured with high precision using narrow-linewidth lasers via Electromagnetically Induced Transparency (EIT) of rubidium vapor seeded into a continuous, inductively coupled radio-frequency (rf) plasma in a few mTorr of argon gas. Without plasma, the Rydberg-EIT spectra exhibit rf modulation sidebands caused by electric- and magnetic-dipole transitions in the rf drive coil. With the plasma present, the rf modulation sidebands vanish due to screening of the rf drive field from the plasma interior. The lineshapes of the EIT spectra in the plasma reflect the plasma's Holtsmark microfield distribution, allowing us to determine plasma density and collisional line broadening over a range of pressures and rf drive powers. The work is expected to have applications in non-invasive spatio-temporal electric-field diagnostics of low-pressure plasma, plasma sheaths, process plasma and dusty plasma.
We introduce an all-optical quantum-enhanced diagnostic for electric fields in low-temperature plasmas. Trace amounts of rubidium vapor, added to an argon plasma, allow us to employ spectrally narrow electric field-sensitive optical resonances via the quantum optical effect of Rydberg electromagnetically induced transparency. This non-invasive technique enables measurements of electric fields in plasma with a 1~V/cm precision and a 1.5~V/cm lower detection limit. By collecting the fluorescence from the illuminated region of interest, we reconstruct a 2D spatial profile of the electric field magnitude with 56μm resolution. As a proof-of-principle demonstration, we measured the changes in the 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.
Quantum sensing exploits the sensitivity of quantum systems to their environment, translating external fields and forces into measurable shifts in quantum-mechanical observables. Neutral atoms constitute a highly effective and scalable sensing platform owing to their identical nature and extended coherence times. This dissertation investigates two implementations of atom-based quantum sensing: electric field diagnostics in low-pressure plasma discharges using Rydberg electromagnetically induced transparency (EIT), and inertial sensing via tractor atom interferometry (TAI). Non-invasive electric field measurement is crucial for understanding plasma dynamics without disturbing the local environment, for which high-resolution, coherent spectroscopy of Rydberg states via EIT is a promising candidate. Deploying EIT in plasma environments requires a systematic characterization of collisional effects. To this end, Rydberg-EIT is analyzed in rubidium vapor interacting with plasma precursor gases such as argon, neon, and nitrogen at pressures up to 5 Torr. The observed frequency shifts and collisional broadening are consistent with semiclassical predictions from the Fermi pseudopotential model. Crucially, collisional broadening remains narrower than typical EIT linewidths below 100 mTorr, identifying this pressure range as an operational window for EIT-based plasma field diagnostics. Rydberg-EIT is subsequently applied to a low-pressure, inductively coupled plasma (ICP). In a custom ultra-high-vacuum plasma chamber, Rydberg Stark shifts of rubidium tracers seeded into a continuous argon discharge are mapped via EIT. Prior to plasma ignition, Rydberg spectra exhibit modulation sidebands driven by both electric and magnetic near-fields of the ICP coil. Upon ignition, the bulk plasma screens the rf drive field, suppressing the sidebands. The resulting in-plasma lineshapes are instead governed by V/cm-scale plasma microfields and collisional broadening. Modeling the microfield with a Holtsmark distribution enables the extraction of plasma electron densities as a function of pressure and rf power. By resolving a Rydberg resonance whose lineshape is governed by the plasma environment rather than by spectroscopic limits, these measurements establish a framework for sensitive and non-invasive plasma field diagnostics. The second part of the dissertation investigates inertial sensing via a tractor atom interferometer (TAI). Unlike free-space propagation, TAI utilizes continuous three-dimensional confinement and coherent atomic transport. This mitigates wave packet dispersion, guarantees path closure, permits variable holding times, and enables complex spatial trajectories. The proposed experimental framework employs a Laguerre-Gaussian ``pinwheel" optical lattice to drive multi-loop interferometric sequences. Numerical simulations confirm that TAI implementations may achieve rotation sensitivities comparable to those of established free-space interferometers. In the fast-transport regime required for large enclosed areas, where nonadiabatic excitations would otherwise degrade contrast, quantum optimal control is used to design acceleration sequences that remain fast while preserving coherence. These results illustrate the versatility of neutral atoms as a sensing platform, probing electromagnetic fields through their internal structure and inertial forces through their center-of-mass motion.
Rydberg atoms are neutral atoms excited to high principal quantum number states, which endows them with exaggerated properties such as large electric dipole moments, long lifetimes, and extreme sensitivity to external electromagnetic fields. These characteristics form the foundation of Rydberg atom-based sensors, an emerging class of quantum devices capable of optically detecting electric fields across frequencies from DC to the terahertz regime. Rydberg-based electrometry operates through both Autler–Townes (AT) splitting of resonant Rydberg transitions and Stark-shift measurements for high-frequency or far-detuned fields, enabling broadband field sensing from DC to the THz regime. Using ladder-type electromagnetically induced transparency (EIT) and AT splitting, these sensors enable non-invasive, SI-traceable measurements of field amplitude, frequency, phase, and polarization. Recent developments have demonstrated broadband electric field probes, voltage calibration standards, and compact RF receivers based on thermal vapor cells and integrated photonic architectures. Furthermore, innovations in multi-photon EIT, superheterodyne readout, and multi wave mixing have expanded the dynamic range and bandwidth of Rydberg-based electrometry. Despite challenges related to environmental perturbations, linewidth broadening, and laser stabilization, ongoing advances in atomic control, hybrid photonic integration, and EIT-based readout promise scalable, chip-compatible sensors. This review summarizes the physical principles, experimental progress, and emerging applications of Rydberg atom-based sensing, emphasizing their potential for next generation quantum metrology, wireless communication, and precision field mapping.