Quantum diamond microscopy with optimized magnetic field sensitivity and sub-ms temporal resolution

TL;DR

This paper presents an optimized quantum diamond microscopy technique with enhanced magnetic sensitivity and sub-millisecond temporal resolution, enabling detailed visualization of bio-magnetic fields in biological tissues.

Contribution

The authors develop a lock-in-based wide-field quantum diamond microscopy with improved sensitivity through double resonance and magnetic field alignment, achieving fast imaging capabilities.

Findings

Achieved a mean volume-normalized per pixel sensitivity of 43.9 nT μm^{1.5}/Hz^{0.5}

Demonstrated sub-ms temporal resolution (~0.4 ms) in quantum diamond microscopy

Enabled potential mapping of neuronal activity with micrometer spatial resolution.

Abstract

Quantum diamond magnetometers using lock-in detection have successfully detected weak bio-magnetic fields from neurons, a live mammalian muscle, and a live mouse heart. This opens up the possibility of quantum diamond magnetometers visualizing microscopic distributions of the bio-magnetic fields. Here, we demonstrate a lock-in-based wide-field quantum diamond microscopy, achieving a mean volume-normalized per pixel sensitivity of 43.9 $\mathrm{nT\mu m^{1.5}/Hz^{0.5}}$. We optimize the sensitivity by implementing a double resonance with hyperfine driving and magnetic field alignment along the $<$001$>$ orientation of the diamond. Additionally, we show that sub-ms temporal resolution ($\sim$ 0.4 ms) can be achieved while keeping the per-pixel sensitivity at a few tens of nanotesla per second using quantum diamond microscopy. This lock-in-based diamond quantum microscopy could be a step forward in mapping functional activity in neuronal networks in micrometer spatial resolution.