A portable LED-based diamond magnetometer for outreach and teaching labs

We present a compact, low-cost version of a nitrogen-vacancy center diamond magnetometer, where the standard green excitation laser is replaced with a high-power light-emitting diode. This modification improves safety, reduces cost, and allows the green excitation and red photoluminescence light to be viewed directly during demonstrations. Our magnetometer is simple to assemble and suitable for outreach activities and undergraduate laboratories. We show that this experimental setup can produce optically detected magnetic resonance spectra and respond to nearby magnetic objects, with a sensitivity on the order of 1 μT/Hz. Accompanying supplementary material provides details of the magnetometer construction and suggestions for student investigations to support use in teaching laboratories.