Advanced Quantum Magnetic Microscopy with Solid-state Spin Ensemble in Diamond

Abstract

Solid-state electronic spin systems offer powerful platforms for sensitive magnetic-field detection. A prominent example is the negatively charged nitrogen-vacancy (NV⁻) center in diamond, which provides long spin-coherence times, direct optical readout, and robust operation under ambient conditions. These properties have enabled NV centers to serve as high-performance magnetometers across diverse application areas. The development of the quantum diamond microscope (QDM) has further expanded these capabilities, introducing a wide-field imaging modality that delivers high-spatial-resolution magnetic images enabled by the minimal stand-off distance between the diamond sensor and the sample.

Over the past decade, QDM technology has matured significantly, demonstrating broad utility in bioscience, electronic diagnostics, geology, and condensed-matter physics, and is now transitioning from laboratory instruments to commercial products. However, two major challenges remain. First, most QDM-based magnetic microscopy still relies on optically detected magnetic resonance (ODMR), which constrains both sensitivity and sensing bandwidth. Second, the use of CCD cameras in typical QDM implementations limits temporal resolution and restricts access to advanced pulsed-sensing techniques.

This work advances a next-generation QDM for quantum magnetic microscopy. On the hardware side, we design and construct a QDM platform incorporating a high-speed lock-in camera operating at kiloframes per second and an arbitrary waveform generator (AWG) for executing advanced quantum sensing protocols. These improvements enable the application of established pulsed sensing techniques, previously not demonstrated in a wide-field imaging format, to QDM. We demonstrate static and broadband magnetic imaging using Ramsey sequences, narrowband signal imaging with dynamical decoupling protocols, and nuclear magnetic resonance (NMR) imaging using the coherently averaged synchronized readout (CASR) technique. Finally, we benchmark the system’s sensitivity and spatial resolution, demonstrating substantial improvements enabled by the advanced hardware and pulsed-sensing capabilities. With the enhanced sensitivity and temporal resolution, this work expands the range of signals and phenomena that QDM can image, paving the way for broader scientific and technological applications.