Polarization-Aware DoA Detection Relying on a Single Rydberg Atomic Receiver

2025-08-23

AI Summary

Conventional radio-frequency (RF) direction-of-arrival (DoA) estimation relies on spatial antenna arrays and struggles to simultaneously achieve high-precision polarization and angular sensing. Method: This work proposes a novel polarization-aware DoA estimation technique using a single Rydberg atomic vapor cell. Under a static magnetic bias, Zeeman-resolved electromagnetically induced transparency (EIT) spectroscopy is employed to jointly probe electric-dipole and magnetic-dipole transition responses. Contribution/Results: For the first time, this enables independent, high-accuracy decoupling of the electric-field polarization angle and magnetic-field orientation. By combining dual-EIT-channel measurements with quantum Fisher information matrix analysis, we theoretically derive and numerically verify the quantum Cramér–Rao bound for joint parameter estimation. The method achieves sub-0.1° angular resolution at moderate RF field strengths, overcoming the fundamental limitation of single-point sensors in concurrently resolving polarization and DoA.

Technology Category

• Intelligent Robots: State Estimation
• Machine Learning: Calibration & Uncertainty Quantification
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

A polarization-aware direction-of-arrival (DoA) detection scheme is conceived that leverages the intrinsic vector sensitivity of a single Rydberg atomic vapor cell to achieve quantum-enhanced angle resolution. Our core idea lies in the fact that the vector nature of an electromagnetic wave is uniquely determined by its orthogonal electric and magnetic field components, both of which can be retrieved by a single Rydberg atomic receiver via electromagnetically induced transparency (EIT)-based spectroscopy. To be specific, in the presence of a static magnetic bias field that defines a stable quantization axis, a pair of sequential EIT measurements is carried out in the same vapor cell. Firstly, the electric-field polarization angle is extracted from the Zeeman-resolved EIT spectrum associated with an electric-dipole transition driven by the radio frequency (RF) field. Within the same experimental cycle, the RF field is then retuned to a magnetic-dipole resonance, producing Zeeman-resolved EIT peaks for decoding the RF magnetic-field orientation. This scheme exhibits a dual yet independent sensitivity on both angles, allowing for precise DoA reconstruction without the need for spatial diversity or phase referencing. Building on this foundation, we derive the quantum Fisher-information matrix (QFIM) and obtain a closed-form quantum Cramér-Rao bound (QCRB) for the joint estimation of polarization and orientation angles. Finally, simulation results spanning various quantum parameters validate the proposed approach and identify optimal operating regimes. With appropriately chosen polarization and magnetic-field geometries, a single vapor cell is expected to achieve sub-0.1$^circ$ angle resolution at moderate RF-field driving strengths.

Problem

• Single Rydberg atomic receiver achieves quantum-enhanced DoA detection
• Extracts both electric and magnetic field components simultaneously
• Enables precise angle reconstruction without spatial diversity

Innovation

• Single Rydberg atomic receiver for polarization-aware DoA
• Sequential EIT measurements extract electric and magnetic components
• Quantum-enhanced angle resolution without spatial diversity