Continuous-frequency weak electric field measurement with Rydberg atoms

TL;DR

This paper presents a novel method for continuous, high-sensitivity electric field measurement across a broad frequency range using Rydberg atoms and off-resonant AC Stark effect, with potential for versatile applications.

Contribution

The authors introduce a continuous-frequency electric field measurement technique utilizing off-resonant AC Stark effect in Rydberg atoms, enabling broad frequency detection with high sensitivity.

Findings

Detects electric fields from 2 GHz to 5 GHz using a single Rydberg state.

Achieves a minimum detectable field strength of 2.31 μV/cm.

Demonstrates a linear dynamic range over 65 dB.

Abstract

We demonstrate a continuous frequency electric field measurement based on the far off-resonant AC stark effect in a Rydberg atomic vapor cell. In this configuration, a strong far off-resonant field, denoted as a local oscillator (LO) field, acts as a gain shifting the Rydberg level to a high sensitivity region. An incident weak signal field with a few hundreds of kHz difference from the LO field is mixed with the LO field in Rydberg system to generate an intermediate frequency (IF) signal, which is read out by the Rydberg electromagnetically induced transparency (Rydberg-EIT) spectroscopy. Not like resonant EIT-AT spectra, we realize the electric field measurement of the signal frequency from 2 GHz to 5 GHz using a single Rydberg state. A minimum detectable filed strength is down to 2.31~$\mu$V/cm and a linear dynamic range is over 65~dB. The minimum detectable filed is comparable with a resonant microwave-dressed Rydberg heterodyne receiver using the same system, which is 1.45~$\mu$V/cm. We also show the system has an inherent polarization selectivity feature. Our method can provide a high sensitivity of electric field measurement and be extended to arbitrary frequency measurements.