The quantum diamond microscope (QDM) is a recently developed technology for near-field imaging of magnetic fields with micron-scale spatial resolution. In the present work, we integrate a QDM with a narrowband measurement protocol and a lock-in camera; and demonstrate imaging of radiofrequency (RF) magnetic field patterns produced by microcoils, with spectral resolution ≈1\,Hz. This RF-QDM provides multi-frequency imaging with a central detection frequency that is easily tunable over the MHz-scale, allowing spatial discrimination of both crowded spectral peaks and spectrally well-separated signals. The present instrument has spatial resolution ≈2μm, field-of-view ≈300×300μm2, and per-pixel sensitivity to narrowband fields ∼1nT⋅Hz−1/2. Spatial noise can be reduced to the picotesla scale by signal averaging and/or spatial binning. The RF-QDM enables simultaneous imaging of the amplitude, frequency, and phase of narrowband magnetic field patterns at the micron-scale, with potential applications in real-space NMR imaging, AC susceptibility mapping, impedance tomography, analysis of electronic circuits, and spatial eddy-current-based inspection.
@article{arxiv.2406.15450,
title = {Quantum Diamond Microscope for Narrowband Magnetic Imaging with High Spatial and Spectral Resolution},
author = {Zechuan Yin and Jiashen Tang and Connor A. Hart and John W. Blanchard and Xinyan Xiang and Saipriya Satyajit and Smriti Bhalerao and Tao Tao and Stephen J. DeVience and Ronald L. Walsworth},
journal= {arXiv preprint arXiv:2406.15450},
year = {2024}
}