Proof of the feasibility of a nanocell-based wide-range optical magnetometer.

We present an experimental scheme performing scalar magnetometry based on the fitting of Rb $ {{\rm D}_2} $D line spectra recorded by derivative selective reflection spectroscopy from an optical nanometric-thick cell. To demonstrate its efficiency, the magnetometer is used to measure the inhomogeneous magnetic field produced by a permanent neodymium--iron-boron alloy ring magnet at different distances. The computational tasks are realized by relatively cheap electronic components: an Arduino Due board for external control of the laser and acquisition of spectra, and a Raspberry Pi computer for the fitting.