Nitrogen-Vacancy Ensemble Magnetometry Based on Pump Absorption

TL;DR

This paper presents a novel method for magnetic field sensing using nitrogen-vacancy centers in diamond, leveraging pump-light absorption variations, achieving high sensitivity and bandwidth.

Contribution

It introduces a new absorption-based magnetometry technique with potential for enhanced sensitivity and practical implementation.

Findings

Achieved a noise floor of ~100 nT/√Hz at 125 Hz bandwidth.

Projected shot-noise-limited sensitivity of ~1 pT/√Hz.

Demonstrated effective sensing using a resonant optical cavity.

Abstract

We demonstrate magnetic field sensing using an ensemble of nitrogen-vacancy centers by recording the variation in the pump-light absorption due to the spin-polarization dependence of the total ground state population. Using a 532 nm pump laser, we measure the absorption of native nitrogen-vacancy centers in a chemical vapor deposited diamond placed in a resonant optical cavity. For a laser pump power of 0.4 W and a cavity finesse of 45, we obtain a noise floor of $\sim$ 100 nT/$\sqrt{\textrm{Hz}}$ spanning a bandwidth up to 125 Hz. We project a photon shot-noise-limited sensitivity of $\sim$ 1 pT/$\sqrt{\textrm{Hz}}$ by optimizing the nitrogen-vacancy concentration and the detection method.