Simultaneous mapping of the magnetic field components using near-field microscopy

In this work, we present a near-field scanning optical microscope capable of simultaneously mapping the $x - $ , $y - $ , and $z - $ components of the magnetic field generated by a set of magnetic coils in the ${\text{kHz}}$ range. Using this device, we present two experiments: the observation of the well-known magnetic field of a circular coil and a resolution test. The observations achieved with our instrument are supported by numerically calculated simulations, which confirm the validity of our experimental results. In addition, our instrument is capable of imaging features of the order of $15\;{\text{mm}}$ , representing a resolution of $\lambda /10\,000$ . Our approach establishes an important avenue for the three-dimensional mapping of the electromagnetic field in any spectral range, using the correct configuration of the probe, and opens a new discussion on the resolution of scanning probe microscopes imaging more than one component of the studied field.