High sensitivity measurement of ULF, VLF and LF fields with Rydberg-atom sensor

TL;DR

This paper demonstrates a Rydberg-atom sensor capable of highly sensitive electric field measurements in the ULF, VLF, and LF bands, overcoming low-frequency screening effects with optimized electric field application.

Contribution

The study introduces an optimized Rydberg-atom sensor for low-frequency electric field detection, achieving unprecedented sensitivity and dynamic range in the ULF, VLF, and LF bands.

Findings

Minimum detectable electric fields: 18.0 μV/cm at 1kHz, 6.9 μV/cm at 10kHz, 3.0 μV/cm at 100kHz

Sensitivities: 5.7 μV/cm/√Hz, 2.2 μV/cm/√Hz, 0.95 μV/cm/√Hz for ULF, VLF, LF

Linear dynamic range exceeds 50 dB

Abstract

Fields with frequencies below megahertz are challenging for Rydberg-atom-based measurements, due to the low-frequency electric field screening effect that is caused by the alkali-metal atoms adsorbed on the inner surface of the container. In this paper, we investigate on electric fields measurements in the ULF, VLF and LF bands in a Cs vapor cell with built-in parallel electrodes. With optimization of the applied DC field, we achieve high-sensitive detection of the electric field at frequencies of 1kHz, 10kHz and 100kHz based on Rydberg-atom sensor, with the minimum electric field strength down to 18.0{\mu}V/cm, 6.9{\mu}V/cm and 3.0{\mu}V/cm, respectively. The corresponding sensitivity is 5.7 {\mu}V/cm/{\sqrt{Hz}}, 2.2{\mu}V/cm/{\sqrt{Hz}} and 0.95{\mu}V/cm/{\sqrt{Hz}} for ULF, VLF and LF fields, which is better than 1-cm dipole antenna. Besides, the linear dynamic range of Rydberg-atom sensor is over 50 dB. This work presents the potential to enable more applications that utilize atomic sensing technology in ULF, VLF and LF fields.