Optical Magnetometry based Current Source

TL;DR

This paper introduces an optical magnetometry-based current monitoring system capable of real-time current measurement and stabilization, effectively discriminating true current variations from environmental noise at room temperature.

Contribution

The work presents a novel optical magnetometry system with a configurable coil and real-time digital processing for precise current monitoring and stabilization.

Findings

Achieved current stabilization better than 5×10⁻⁹ for 20 mA.

Demonstrated discrimination of true current changes from environmental effects.

System is adaptable to various current ranges with coil modifications.

Abstract

We present a current monitoring system based on optical magnetometry, which is able to discriminate true current variations from environmental effects at room temperature. The system consists of a dedicated thermally stable magnetic field confining coil and an array of four optically pumped magnetometers arranged in a two-dimensional gradiometer configuration. These magnetometers monitor magnetic field variations inside the coil, which correlate to the variations of the driving current of the coil. The system uses a digital signal-processing unit to extract and record in real time the magnetic field values measured by the magnetometers, which allows a real time monitoring of the current. The system's coil, which is made out of printed circuit boards, can easily be changed to adapt the current-to-field conversion. Thus, we can expand the applicability of this system to a wide range of currents. By using this system to actively feedback control a current source we stabilized a current of 20 mA on a level better than $5 \times 10^{-9}$.