Integrated magneto-optic based magnetometer: classical and quantum limits

TL;DR

This paper introduces a scalable, integrated all-optical magnetometer using silicon photonics and magneto-optic thin films, achieving high sensitivity and dynamic range suitable for various practical applications.

Contribution

The work presents a novel integrated magnetometer design combining silicon photonics with magneto-optic materials, enabling compactness, scalability, and high sensitivity at room temperature.

Findings

Over 80 dB dynamic range achieved.

Sensitivity better than 40 pT/√Hz at room temperature.

Scalable fabrication via foundry manufacturing.

Abstract

Magnetic field sensors with high sensitivity and spatial resolution have profoundly impacted diverse applications ranging from geo-positioning and navigation to medical imaging, materials science, and space exploration. However, the use of high-precision magnetometers is often limited due to their bulky size or low energy efficiency. In this work, we present the design, modeling and an experimental demonstration of an all-optical magnetometer based on silicon integrated photonics heterogeneously integrated with a magneto-optic thin film. By bonding a thin cerium-yttrium iron garnet layer onto an integrated silicon photonic interferometer, small magnetic field fluctuations can be detected through the non-reciprocal phase shift in the sensor. This strategy enables more than 80 dB of dynamic range with better than 40~pT/$\sqrt{\text{Hz}}$ sensitivity at room temperature. Importantly, by leveraging silicon photonics, the core platform is scalable through foundry manufacturing, and the ultra-low power requirements enable complete system integration with on-chip lasers, detectors, and quantum elements for enhanced sensitivity. This work provides a path to realizing a compact, scalable, room temperature magnetometer based on integrated photonic systems, opening new opportunities for ultra-sensitive and ultra-efficient magnetic field detectors.