The QDM or Quantum Diamond Microscope employs a dense layer of fluorescent nitrogen-vacancy (NV) centers near the surface of a transparent diamond chip on which a sample of interest is placed. NV electronic spins are coherently probed with microwaves and optically initialized and read out to provide spatially resolved maps of local magnetic fields. NV fluorescence is measured simultaneously across the diamond surface, resulting in a wide-field, two-dimensional magnetic field image with adjustable spatial pixel size set by the parameters of the imaging system.
Levine, E. V., Turner, M. J., Kehayias, P., Hart, C. A., Langellier, N., Trubko, R., … & Walsworth, R. L. (2019). Principles and techniques of the quantum diamond microscope. Nanophotonics, 8(11), 1945-1973.