Fast scanning nitrogen-vacancy magnetometry by spectrum demodulation

TL;DR

This paper introduces a spectrum demodulation technique that significantly accelerates data acquisition in scanning nitrogen-vacancy magnetometry, enabling real-time, high-resolution magnetic field imaging of samples with large signal variations.

Contribution

The authors develop a novel spectrum demodulation method that increases scanning speed and allows real-time resonance tracking in NV center magnetometry.

Findings

Achieved pixel rates of up to 100 Hz in magnetic field mapping.

Demonstrated high-resolution imaging exceeding one megapixel.

Effective for samples with large magnetic signal ranges.

Abstract

We demonstrate a spectrum demodulation technique for greatly speeding up the data acquisition rate in scanning nitrogen-vacancy center magnetometry. Our method relies on a periodic excitation of the electron spin resonance by fast, wide-band frequency sweeps combined with a phase-locked detection of the photo-luminescence signal. The method can be extended by a frequency feedback to realize real-time tracking of the spin resonance. Fast scanning magnetometry is especially useful for samples where the signal dynamic range is large, of order millitesla, like for ferro- or ferrimagnets. We demonstrate our method by mapping stray fields above the model antiferromagnet $\alpha$-Fe$_2$O$_3$ (hematite) at pixel rates of up to 100\,Hz and an image resolution exceeding one megapixel.