  Wide-field magnetic microscopy using nitrogen-vacancy (NV) centers in diamond
can yield high-quality magnetic images of DC and AC magnetic fields. The unique
combination of micron-scale spatial resolution of scalar or vector fields at
room temperature and parallel camera readout make this an appealing technique
for applications in biology, geology, condensed-matter physics, and
electronics. However, while NV magnetic microscopy has achieved great success
in these areas, historically the accessible frequency range has been limited.
In this paper, we overcome this limitation by implementing the recently
developed technique of quantum frequency mixing. With this approach, we
generate wide-field magnetic images of test structures driven by alternating
currents up to 70 MHz, well outside the reach of DC and Rabi magnetometry
methods. With further improvements, this approach could find utility in
hyperspectral imaging for electronics power spectrum analysis, electronics
diagnostics and troubleshooting, and quantum computing hardware validation.
