Highly Sensitive On-Chip Magnetometer with Saturable Absorbers in Two-Color Microcavities

TL;DR

This paper proposes a scalable on-chip magnetometer leveraging two interacting microcavities with nitrogen vacancy centers in diamond, achieving high sensitivity and spatial resolution through nonlinear optical effects.

Contribution

It introduces a novel design of nested microcavities with different resonances to enhance magnetic-field sensitivity using nitrogen vacancy centers.

Findings

Cavities can improve magnetic-field sensitivity by up to two orders of magnitude.

System behaviors depend on intrinsic and extrinsic parameters, explaining key nonlinearities.

The approach combines high sensitivity with micrometer spatial resolution.

Abstract

Interacting resonators can lead to strong non-linearities but the details can be complicated to predict. In this work, we study the non-linearities introduced by two nested microcavities that interact with nitrogen vacancy centers in a diamond waveguide. Each cavity has differently designed resonance; one in the green and one in the infrared. The magnetic-field dependence of the nitrogen vacancy center absorption rates on the green and the recently observed infrared transitions allows us to propose a scalable on-chip magnetometer that combines high magnetic-field sensitivity and micrometer spatial resolution. By investigating the system behaviors over several intrinsic and extrinsic parameters, we explain the main non-linearities induced by the NV centers and enhanced by the cavities. We finally show that the cavities can improve the magnetic-field sensitivity by up to two orders of magnitudes.