Calibration of electric fields in low-frequency off-resonant Rydberg receivers

TL;DR

This paper demonstrates Rydberg atom-based electric field sensing across a broad frequency range, utilizing a novel excitation scheme and waveguide setup, achieving high sensitivity and accurate calibration in low-frequency regimes.

Contribution

It introduces a three-photon excitation scheme and a TEM line waveguide for low-frequency Rydberg electric field sensing, with validated models and high sensitivity.

Findings

Achieved a noise-equivalent field of 106(4) μV/m/√Hz at 300 MHz

Validated a phenomenological model of vapor cell material properties

Characterized noise-equivalent fields in the ULF-VLF band

Abstract

We present results on Rydberg atom-based electric field sensing in the range of 1 kHz - 300 MHz, using a three-photon Rydberg excitation scheme and a transverse electromagnetic (TEM) line waveguide to apply low-frequency rf fields to the cell. Measurements of low-frequency screening in quartz and sapphire vapor cells show excellent agreement with a phenomenological model of the effective vapor cell material properties based on an electrical 2-port measurement of the TEM line. We achieve a best noise-equivalent field of 106(4) $\mathrm{\frac{\mu V}{m \sqrt{Hz}}}$ at 300 MHz and characterize noise-equivalent fields in the ultra-low to very-low frequency (ULF-VLF) band.