Quantitative study of the response of a single NV defect in diamond to magnetic noise

TL;DR

This study quantitatively investigates how magnetic noise affects the spin relaxation of a single NV defect in diamond, demonstrating a simple optical method to detect nanoscale magnetic noise sources.

Contribution

It provides a calibrated, tunable magnetic noise application to a single NV defect and models the resulting PL quenching as a new all-optical detection technique.

Findings

Increased magnetic noise accelerates NV spin relaxation.

Spin relaxation rate correlates with PL signal reduction.

The simplified three-level model explains PL quenching.

Abstract

The nitrogen-vacancy (NV) defect in diamond is an efficient quantum sensor of randomly fluctuating signals via relaxometry measurements. In particular, the longitudinal spin relaxation of the NV defect accelerates in the presence of magnetic noise with a spectral component at its electron spin resonance frequency. We look into this effect quantitatively by applying a calibrated and tunable magnetic noise on a single NV defect. We show that an increase of the longitudinal spin relaxation rate translates into a reduction of the photoluminescence (PL) signal emitted under continuous optical illumination, which can be explained using a simplified three-level model of the NV defect. This PL quenching mechanism offers a simple, all-optical method to detect magnetic noise sources at the nanoscale.