Highly sensitive on-chip magnetometer with saturable absorbers in two-color microcavities

摘要

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