All-Optical Photoluminescence Response of Nitrogen-Vacancy Ensembles in Diamond at Low Magnetic Fields

TL;DR

This study demonstrates all-optical photoluminescence-based magnetometry at low magnetic fields using nitrogen-vacancy centers in diamond, highlighting its potential for simpler, low-power magnetic sensing applications.

Contribution

It provides the first detailed analysis of room-temperature AO-PL contrast in NV ensembles at low magnetic fields, correlating experimental results with theoretical models.

Findings

AO-PL contrast varies with magnetic field magnitude and orientation.

Maximum contrast depends on NV concentration and laser power.

AO-PL sensing offers advantages over traditional ODMR methods.

Abstract

All-optical (AO), microwave-free magnetometry using nitrogen-vacancy (NV) centers in diamond is attractive due to its broad sample compatibility and reduced experimental complexity. In this work, we investigate room-temperature AO photoluminescence (PL) at low magnetic fields (<2 mT) using diamonds with NV ensembles at ppm concentrations. Measured AO-PL contrast features as a function of applied magnetic field magnitude and direction are correlated with near-degenerate NV electronic spin and hyperfine transitions from different NV orientations within the diamond host. Reasonable agreement is found between low-field AO-PL measurements and model-based simulations of the effects of resonant dipolar interactions between NV centers. Maximum observed AO-PL contrast depends on both NV concentration and laser illumination intensity at 532 nm. These results imply different optimal conditions for low-field AO NV sensing compared to conventional optically detected magnetic resonance (ODMR) techniques, suggesting new research and application opportunities using AO measurements with lower system complexity, size, weight, and power.