Level anti-crossing magnetometry with color centers in diamond

TL;DR

This paper explores two methods to enhance diamond-based magnetometry using NV centers at the ground-state level anti-crossing, achieving high sensitivity without microwaves by optimizing feature parameters and detection techniques.

Contribution

It introduces two novel approaches for improving NV center magnetometry sensitivity by utilizing the GSLAC feature and transmission detection, without requiring microwave excitation.

Findings

Achieved a magnetometric sensitivity of 0.45 nT/√Hz.

Enhanced GSLAC contrast through absorption detection.

Demonstrated microwave-free sensing with high precision.

Abstract

Recent developments in magnetic field sensing with negatively charged nitrogen-vacancy centers (NV) in diamond employ magnetic-field (MF) dependent features in the photoluminescence (PL) and eliminate the need for microwaves (MW). Here, we study two approaches towards improving the magnetometric sensitivity using the ground-state level anti-crossing (GSLAC) feature of the NV center at a background MF of 102.4\,mT. Following the first approach, we investigate the feature parameters for precise alignment in a dilute diamond sample; the second approach extends the sensing protocol into absorption via detection of the GSLAC in the diamond transmission of a 1042\,nm laser beam. This leads to an increase of GSLAC contrast and results in a magnetometer with a sensitivity of 0.45\,nT/$\sqrt{\text{Hz}}$ and a photon shot-noise limited sensitivity of 12.2 pT/$\sqrt{\rm{Hz}}$.