Distributed Quantum Fiber Magnetometry

TL;DR

This paper introduces a novel fiber-based distributed quantum magnetometry system using NV centers, enabling long-range magnetic sensing over 90 meters with multiple detection sites, suitable for various remote sensing applications.

Contribution

It presents a new continuous fiber architecture with embedded NV diamond sensors, allowing scalable, distributed quantum magnetic sensing over extended lengths.

Findings

Distributed sensing over 90 meters achieved

102 detection sites embedded in a single fiber

Sensitivity of 63 nT/Hz^{1/2} per site

Abstract

Nitrogen-vacancy (NV) quantum magnetometers offer exceptional sensitivity and long-term stability. However, their use to date in distributed sensing applications, including remote detection of ferrous metals, geophysics, and biosensing, has been limited due to the need to combine optical, RF, and magnetic excitations into a single system. Existing approaches have yielded localized devices but not distributed capabilities. In this study, we report on a continuous system-in-a-fiber architecture that enables distributed magnetic sensing over extended lengths. Key to this realization is a thermally drawn fiber that has hundreds of embedded photodiodes connected in parallel and a hollow optical waveguide that contains a fluid with NV diamonds. This fiber is placed in a larger coaxial cable to deliver the required RF excitation. We realize this distributed quantum sensor in a water-immersible 90-meter-long cable with 102 detection sites. A sensitivity of 63 nT Hz-1/2 per site, limited by laser shot noise, was established along a 90 m test section. This fiber architecture opens new possibilities as a robust and scalable platform for distributed quantum sensing technologies.